Multi-layer insulated glass unit comprising low CTE glass layer

Abstract

To provide an insulated glass unit with improved thermal and insulative properties, which can satisfy other design constraints, including reduced weight, reduced thickness, and / or reduced manufacturing cost.SOLUTION: An insulated glass unit includes at least a first glass layer 10, a second glass layer 20, and a third glass layer 30 disposed therebetween. The third glass layer is separated from the first glass layer and the second glass layer by first and second sealed gap spaces. The third glass layer has a lower CTE compared to the CTE of the first and / or second glass layers. In some instances, the third glass layer has a CTE of less than 70×10-7 / °C over a temperature range of 0-300°C.SELECTED DRAWING: Figure 1

Description

Description of Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 62 / 609,069, filed on December 21, 2017, the contents of which are hereby incorporated by reference in their entirety. This application is also a divisional application of Japanese Patent Application No. 2023-177,419, filed on October 13, 2023, which is a divisional application of Japanese Patent Application No. 2020-534,250, filed on December 20, 2018.

Technical Field

[0002] The present disclosure broadly relates to insulating glass units that include at least one low CTE glass layer. More particularly, the present disclosure relates to multi-layer insulating glass units that include at least one glass layer having a CTE of less than 70×10 -7 / °C and that can be used as multi-pane windows.

Background Art

[0003] Insulating glass units (IGUs) are useful as components in a wide variety of applications, including components in buildings, automobiles, displays, and appliances. IGUs may be used as multi-pane windows in buildings or automobiles to provide insulation from external environmental temperatures. An IGU typically includes two or more glass sheets that are sealed at their peripheral edges by a seal. The glass sheets are spaced apart, and the space between each glass sheet can be filled with an inert gas, such as argon or krypton, or an inert gas mixture, once sealed. By doing so, the insulation or thermal performance of the IGU can be improved. In addition to thermal and insulating performance, IGUs will typically need to meet other design constraints, including reduction in mass, reduction in thickness, improvement in light transmittance, improvement in mechanical strength, and / or reduction in manufacturing cost.

[0004] A triple IGU (e.g., three-pane glass having two air cavities) exhibits improved thermal and insulating performance compared to a double IGU (e.g., two-pane glass having one air cavity), as indicated by an improvement of 20-30% or more in the solar heat gain coefficient (SHGC) and / or the insulating U-value. However, the triple IGU may not meet other design constraints such as a reduction in mass, thickness, and / or manufacturing cost. The additional mass, thickness, and / or manufacturing cost associated with the additional glass layer may negatively affect the IGU so as not to meet the design requirements for a particular application.

[0005] In addition, since the central glass layer is insulated on both sides, it can reach a much higher temperature, and thus a higher stress level, than the glass layer facing the inside and the glass layer facing the outside. To reduce the possibility of breakage, the central glass layer is often thermally tempered or heat-strengthened to improve its mechanical strength. However, the heat-strengthening process may require a thicker glass substrate, e.g., a glass substrate with a thickness of at least about 2-3 mm. As described above, a glass layer of this thickness may undesirably increase the overall thickness and / or overall mass of the IGU, and the additional tempering process may increase the manufacturing cost of the IGU. Furthermore, thermal tempering can warp the central glass layer and / or cause its birefringence, thereby degrading the optical quality of the IGU. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Therefore, it would be advantageous to provide an IGU with improved thermal and / or insulating properties that can also satisfy other design constraints, including but not limited to a reduction in mass, thickness, and / or manufacturing cost. MEANS FOR SOLVING THE PROBLEM

[0007] In various embodiments, the present disclosure relates to a thermally insulating glass unit including a first glass layer, a second glass layer, and a third glass layer disposed between the first and second glass layers, a first sealed gap interval defined between the first and third glass layers, and a second sealed gap interval defined between the second and third glass layers, wherein the third glass layer has a coefficient of thermal expansion (CTE) in the temperature range of 0 to 300 °C of less than 70×10 -7 / °C.

[0008] The present disclosure also relates to a thermally insulating glass unit including a first glass layer having a coefficient of thermal expansion CTE1, a second glass layer having a coefficient of thermal expansion CTE2, and a third glass layer disposed between the first and second glass layers and having a coefficient of thermal expansion CTE3, a first sealed gap interval defined between the first and third glass layers, and a second sealed gap interval defined between the second and third glass layers, wherein at least one of CTE1 > CTE3 or CTE2 > CTE3 holds when measured over the temperature range of 0 to 300 °C.

[0009] According to various embodiments, at least one of the first and second glass layers may have a thickness of more than about 2 mm. At least one of the first, second, and third glass layers may be chemically strengthened or thermally tempered. In certain embodiments, at least one of the inner surfaces of the first glass layer, the inner surface of the second glass layer, or the major surfaces of the third glass layer may be coated with at least one low emissivity coating. According to further embodiments, at least one major surface of the third glass layer may be at least partially patterned with ink or light scattering features. In still further embodiments, at least one type of insulating gas or a mixture thereof with air can be used to fill the first and / or second sealed gap intervals.

[0010] The insulating glass unit disclosed herein may, in certain embodiments, include a fourth glass layer disposed between a first and a second glass layer, and a third sealed gap interval defined between a third glass layer and the fourth glass layer. In some embodiments, the fourth glass layer may have a coefficient of thermal expansion (CTE) over a temperature range of 0 to 300 °C of less than 70×10 -7 / °C. The third and / or fourth glass layers may, in various embodiments, be made from aluminosilicate glass such as alkaline earth aluminosilicate glass or alkali-free aluminosilicate glass. According to non-limiting embodiments, the third and / or fourth glass layers can be made from float-formed glass. The thickness of the third and / or fourth glass layer may be less than about 2 mm, or, in alternative embodiments, greater than about 1.5 mm.

[0011] Additional features and advantages of the present disclosure are described in the following detailed description, and some of them will be readily apparent to those skilled in the art from that description, or will be recognized by practicing the methods as described herein, including the following detailed description, the claims, and the accompanying drawings.

[0012] Both the foregoing general description and the following detailed description illustrate various embodiments of the present disclosure and are intended to provide an overview or framework for understanding the nature and characteristics of the claims. It will be understood that the accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the present disclosure and, together with the description, serve to explain the principles and operation of the present disclosure.

[0013] The following detailed description can be further understood when read in conjunction with the following drawings.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0015] Here, various embodiments of the present disclosure will be discussed with reference to FIGS. 1 to 5. These figures show exemplary embodiments of the IGU and their members, features, or properties. The previous general description is for the purpose of providing an overview of the devices described in the claims, and various aspects will be discussed more specifically throughout the present disclosure in relation to the non-limitingly shown embodiments, and these embodiments are interchangeable with each other within the context of the present disclosure.

[0016] A heat-insulating glass unit including a first glass layer, a second glass layer, a third glass layer disposed between the first and second glass layers, a first sealed gap interval defined between the first and third glass layers, and a second sealed gap interval defined between the second and third glass layers, wherein the third glass layer has a coefficient of thermal expansion (CTE) over a temperature range of 0 to 300°C less than 70×10 -7 / °C, is disclosed herein.

[0017] A heat-insulating glass unit including a first glass layer having a coefficient of thermal expansion CTE1, a second glass layer having a coefficient of thermal expansion CTE2, and a third glass layer having a coefficient of thermal expansion CTE3 disposed between the first and second glass layers, a first sealed gap interval defined between the first and third glass layers, and a second sealed gap interval defined between the second and third glass layers, wherein at least one of CTE1 > CTE3 or CTE2 > CTE3 holds when measured over a temperature range of 0 to 300°C, is also disclosed herein.

[0018] An exemplary IGU100 is shown in FIG. 1, and this IGU includes three glass layers 10, 20, and 30. The first (outer) glass layer 10 can be positioned such that its outer surface 12 faces the surrounding external environment. The second (inner) glass layer 20 can be positioned such that its outer surface 22 faces the interior, for example, the interior of a building, a vehicle, or an appliance. The third (central) glass layer 30 can be disposed between the glass layers 10, 20 and spaced apart from them. The third glass layer 30 can be positioned substantially parallel to the first and second glass layers 10, 20. All of the glass layers 10, 20, 30 can be optically transparent, or one or more of those layers, or one or more portions thereof, can be translucent, opaque, or semi-opaque.

[0019] According to various embodiments, the first and second glass layers 10, 20 may be thicker than the third glass layer 30. In some embodiments, the glass layers 10, 20 may have a thickness ranging from about 2 mm to about 10 mm, such as from about 3 mm to about 8 mm, from about 4 mm to about 7 mm, or from about 5 mm to about 6 mm, including all ranges and partial ranges therebetween. In non-limiting embodiments, the first and second glass layers 10, 20 can be made of soda-lime glass, but other glass types can also be used, such as aluminosilicate and alkali aluminosilicate glasses, or other similar glasses, without limitation. The coefficient of thermal expansion (CTE) of the first and / or second glass layers 10, 20, in various embodiments, is greater than about 75×10 -7 / °C, greater than about 80×10 -7 / °C, greater than about 85×10 -7 / °C, greater than about 90×10 -7 / °C, greater than about 95×10 -7 / °C, or greater than about 10×10 -6 / °C, etc., greater than about 70×10 -7 / °C, for example, ranging from about 70×10 -7 / °C to about 15×10 -6 / °C.

[0020] According to various embodiments, one or both of the first and second glass layers 10, 20 can be strengthened, for example, by thermal tempering, chemical strengthening, or other similar processes, to improve the mechanical strength of one or both of these layers. The first and second glass layers 10, 20 can be manufactured, in some embodiments, by a float or fusion draw manufacturing process.

[0021] In certain embodiments of the present disclosure, the inner surface 14 of the first glass layer 10 can be partially or completely coated with at least one first coating 16, such as a low emissivity coating to improve thermal performance. Low emissivity coatings are known in the art and can include, without limitation, sputtered coatings, pyrolytic coatings, etc., containing one or more metals and / or metal oxides, such as silver, titanium, and fluorine-doped tin oxide. Alternatively, or in addition, the inner surface 24 of the second glass layer 20 can be partially or completely coated with at least one second coating 26. The first and second coatings 16 and 26 can be the same or different depending on the desired properties and / or end use of the IGU. Combinations of coatings may also be used. In various embodiments, one or both of the coatings 16, 26 can be optically transparent.

[0022] In non-limiting embodiments, the third glass layer 30 can be thinner than the first and second glass layers 10, 20. In some embodiments, the third glass layer 30 can have a thickness of less than about 2 mm, such as from about 0.1 mm to about 1.5 mm, from about 0.3 mm to about 1.2 mm, from about 0.5 mm to about 1 m, from about 0.6 mm to about 0.9 m, or from about 0.7 mm to about 0.8 m, including all and partial ranges therebetween. According to further embodiments, the third glass layer 30 can have a thickness greater than 1.5 mm, and even further greater than 2 mm, such as ranging from about 1.5 mm to about 4 mm, or from about 2 mm to about 3.5 mm, or from about 2.5 mm to about 3 mm, including all and partial ranges therebetween.

[0023] In a non-limiting embodiment, the third glass layer 30 can be made of aluminosilicate glass, such as alkaline earth aluminosilicate glass, or alkali-free aluminosilicate glass, or other similar glass types. Exemplary commercially available glass products include, but are not limited to, Corning® Willow®, "EAGLE XG", and Lotus® glass. According to various embodiments, the third glass layer 30 can be strengthened, for example, by thermal tempering, chemical strengthening, or other similar processes, to improve the mechanical strength of this layer. The third glass layer 30 can be manufactured, in some embodiments, by a float or fusion draw manufacturing process.

[0024] According to various embodiments, the third glass layer 30 can have a lower CTE compared to the CTEs of the first and / or second glass layers 10, 20. As used herein, CTE refers to the coefficient of thermal expansion of a specified glass layer measured, for example, at a temperature of about 20 °C over a temperature range of 0 to 300 °C. In certain embodiments, the CTE of the third glass layer (CTE3) is less than about 60×10 -7 / °C, less than about 50×10 -7 / °C, less than about 45×10 -7 / °C, less than about 40×10 -7 / °C, less than about 35×10 -7 / °C, less than about 30×10 -7 / °C, or less than about 25×10 -7 / °C, etc., and can be less than about 70×10 -7 / °C, for example, ranging from about 10×10 -7 / °C to about 70×10 -7 / °C. In additional embodiments, the CTE of the first glass layer (CTE1) and / or the CTE of the second glass layer (CTE2) is such that CTE1 > CTE3 and / or CTE2 > CTE3, or CTE1 ≧ 2 * CTE3 and / or CTE2 ≧ 2 * CTE3, or CTE1 ≧ 2.5 *CTE3 and / or CTE2 ≥ 2.5 * CTE3, or CTE1 ≥ 3 * CTE3 and / or CTE2 ≥ 3 * CTE3, etc., may be greater than CTE3.

[0025] Although not shown in FIG. 1, one or both major surfaces of the third glass layer 30 may be partially or completely coated with at least one coating, such as the low-emissivity coating described above with respect to coatings 16, 26. Alternatively, or in addition, one or both major surfaces of the third glass layer 30 may be partially or completely patterned with ink and / or surface features, such as decorative ink, light-scattering ink, and / or light-scattering surface features. Bulk scattering features located within the underlying glass substrate may also be provided within the third glass layer 30, for example, by laser patterning. Surface scattering features may also be manufactured by laser patterning. When coatings and / or patterns are provided on both major surfaces of the third glass layer 30, these coatings and / or patterns may be the same or different, depending on the desired properties and / or end use of the IGU. Combinations of coatings and combinations of surface patterns may also be used. In additional embodiments, the third glass layer 30 may include at least one coating and at least one of ink, surface features, and / or bulk features. Of course, such coatings, patterns, and / or features may be similarly provided on the first and second glass layers 10, 20.

[0026] Referring again to FIG. 1, the third glass layer 30 and the outer glass layer 10 can be spaced apart, and a first gap interval 15 can be defined therebetween. The third glass layer 30 and the second glass layer 20 can be spaced apart, and a second gap interval 25 can be defined therebetween. Both gap intervals 15, 25 can be sealed by the sealant assemblies 18, 28, and these assemblies may be the same or different. Exemplary sealant assemblies can be formed from a polymeric seal such as silicone rubber or other sealing materials. The gap intervals 15, 25 can be filled with an inert gas, which will further improve the thermal performance of the IGU. Suitable inert gases include, but are not limited to, argon, krypton, xenon, and combinations thereof. Mixtures of inert gases or mixtures of one or more inert gases and air can also be used. Exemplary non-limiting inert gas mixtures include 90 / 10 or 95 / 5 argon / air mixtures, 95 / 5 krypton / air mixtures, or 22 / 66 / 12 argon / krypton / air mixtures. Other ratios of inert gases or inert gases and air can also be used depending on the desired thermal performance and / or end use of the IGU. According to various embodiments, the gases used to fill the gap intervals 15, 25 may be the same or different.

[0027] The gas pressure within the first gap interval 15 and the second gap interval 25 may be the same or different. The gas pressure difference may be due to, for example, the difference in the average gas temperature within the two intervals. For example, the gas within the first gap interval 15 may be warmer than the gas within the second gap interval 25 depending on the relative ambient temperature and the internal temperature, or vice versa. The differential pressure between the two gap intervals 15, 25 may be sufficient to bend or curve this layer depending on the thickness of the third glass layer 30. To prevent curving, in some embodiments, at least one channel or opening is provided in the third glass layer 30 to allow the gas within the gap interval 15 to contact the gas within the gap interval 25. The opening may be provided, for example, by drilling one or more orifices or holes in the third glass layer 30.

[0028] Alternatively, as shown in FIG. 3, for example, one or more corners of the third glass layer 30 may be cut off or punched out by mechanical scribing and breaking, or laser cutting. Therefore, the outer peripheral shape of the third glass layer 30 may be changed so as to reduce the possibility of the glass layer chipping and / or cracking. When sealing the third glass layer 30 within the IGU, the cut corners 55 can provide a channel through which gas from the gap intervals 15, 25 can contact each other. This contact can eliminate or reduce the differential pressure between the two gap intervals, thereby reducing or eliminating the curvature of the third glass layer 30.

[0029] Referring now to FIG. 2, an alternative IGU 200 is shown that includes four glass layers 10, 20, 30, 40. The illustrated embodiment is similar to that of FIG. 1 except that the IGU 200 includes an additional fourth (central) glass layer 40. The central glass layers 30, 40 are disposed between the first and second glass layers 10, 20.

[0030] In a non-limiting embodiment, the fourth glass layer 40 may be thinner than the first and second glass layers 10, 20. In some embodiments, the fourth glass layer 40 may have a thickness of less than about 2 mm, such as from about 0.1 mm to about 1.5 m, from about 0.3 mm to about 1.2 m, from about 0.5 mm to about 1 m, from about 0.6 mm to about 0.9 m, or from about 0.7 mm to about 0.8 m, including all ranges and sub-ranges therebetween. According to further embodiments, the fourth glass layer 40 may have a thickness greater than 1.5 mm, and even further greater than 2 mm, such as ranging from about 1.5 mm to about 4 mm, or from about 2 mm to about 3.5 mm, or from about 2.5 mm to about 3 mm, including all ranges and sub-ranges therebetween. The thickness of the fourth glass layer 40 may be the same as or different from the thickness of the third glass layer 30.

[0031] In a non-limiting embodiment, the fourth glass layer 40 can be made from aluminosilicate glass, such as alkaline earth aluminosilicate glass, or alkali-free aluminosilicate glass, or other similar glass types. Exemplary commercially available glass products include, but are not limited to, "Corning", "Willow", "EAGLE XG", and "Lotus" glass. According to various embodiments, the fourth glass layer 40 can be strengthened, for example, by thermal tempering, chemical strengthening, or other similar processes, to improve the mechanical strength of this layer. The fourth glass layer 40 can be manufactured, in some embodiments, by a float or fusion draw manufacturing process. The composition of the fourth glass layer 40 may be the same as or different from the composition of the third glass layer 30. Similarly, the mechanical properties of the fourth glass layer 40, such as the degree of strengthening, may be the same as or different from the mechanical properties of the third glass layer 30.

[0032] According to various embodiments, the fourth glass layer 40 may have a lower CTE compared to the CTE of the first and / or second glass layers 10, 20. In certain embodiments, the CTE of the fourth glass layer (CTE4) is about 60×10-7 / °C or less, about 50×10 -7 / °C or less, about 45×10 -7 / °C or less, about 40×10 -7 / °C or less, about 35×10 -7 / °C or less, about 30×10 -7 / °C or less, or about 25×10 -7 / °C or less, such as about 70×10 -7 / °C or less, for example, about 10×10 -7 / °C to about 70×10 -7 / °C. In additional embodiments, the CTE of the first glass layer (CTE1) and / or the CTE of the second glass layer (CTE2) is such that CTE1 > CTE4 and / or CTE2 > CTE4, or CTE1 ≧ 2 * CTE4 and / or CTE2 ≧ 2 * CTE4, or CTE1 ≧ 2.5 * CTE4 and / or CTE2 ≧ 2.5 * CTE4, or CTE1 ≧ 3 * CTE4 and / or CTE2 ≧ 3 * CTE4, etc., may be greater than CTE4. CTE3 and CTE4 may be the same or different. According to non-limiting embodiments, CTE3 is substantially equal to CTE4.

[0033] Although not shown in FIG. 2, one or both of the major surfaces of the third glass layer 30 and / or the fourth glass layer 40 may be partially or completely coated with at least one coating, such as the low emissivity coating described above with respect to coatings 16, 26 (see FIG. 1). Alternatively, or in addition, one or both of the major surfaces of the third glass layer 30 and / or the fourth glass layer 40 may be partially or completely patterned with ink and / or surface features, such as decorative ink, light scattering ink, and / or light scattering surface features. Bulk scattering features located within the underlying glass substrate may also be provided within the third glass layer and / or the fourth glass layer 30, 40, for example, by laser patterning. Surface scattering features may also be manufactured using laser patterning. The coatings and / or surface patterns on one or both of the major surfaces of the third glass layer and / or the fourth glass layer 30, 40 may be the same or different depending on the desired properties and / or end use of the IGU. Combinations of coatings and combinations of surface patterns may also be used. In additional embodiments, the third and / or fourth glass layers 30, 40 may include at least one coating and at least one of ink, surface features, and / or bulk features.

[0034] The third glass layer 30 and the outer glass layer 10 can be spaced apart, and a first gap interval 15 can be defined therebetween. The third glass layer 30 and the fourth glass layer 40 can be spaced apart, and a third gap interval 35 can be defined therebetween. The fourth glass layer 40 and the inner glass layer 20 can be spaced apart, and a fourth gap interval 45 can be defined therebetween. The gap intervals 15, 35, 45 can be sealed by sealant assemblies 18, 38, 48, and these assemblies may be the same or different. Exemplary sealant assemblies have been described previously, and exemplary inert gases and inert gas mixtures for filling the gap intervals were disclosed previously with reference to FIG. 1. According to various embodiments, the gases used to fill the gap intervals 15, 35, 45 may be the same or different. The fourth glass layer 40 may also include one or more cut corners (see FIG. 3).

[0035] Referring to FIGS. 1-2, the thicknesses of the gap spacings 15, 25, 35, 45 can vary depending on the IGU structure and can range from about 6 mm to about 18 mm, such as from about 7 mm to about 16 mm, from about 8 mm to about 14 mm, or from about 10 mm to about 12 mm, including all ranges and partial ranges therebetween. The thicknesses of the gap spacings 15, 25 (FIG. 1) or the gap spacings 15, 35, 45 (FIG. 2) may be the same or different. The total thickness of the IGU 100 can be about 40 mm or less, such as about 36 mm or less, about 32 mm or less, about 30 mm or less, about 28 mm or less, or about 26 mm or less, including all ranges and partial ranges therebetween. In some embodiments, a low U-value is obtained, which represents an improvement in thermal insulation properties, when the thickness of the gap spacing ranges from about 14 mm to about 16 mm and the total thickness of the IGU 100 ranges from about 36 mm to about 40 mm. The total thickness of the IGU 200 can be about 60 mm or less, such as about 56 mm or less, about 54 mm or less, about 50 mm or less, about 40 mm or less, about 30 mm or less, or about 26 mm or less, including all ranges and partial ranges therebetween. In some embodiments, a low U-value is obtained, which represents an improvement in thermal insulation properties, when the thickness of the gap spacing ranges from about 16 mm to about 18 mm and the total thickness of the IGU 200 ranges from about 54 mm to about 60 mm.

[0036] The glass layers of FIGS. 1-3 are referred to herein as a single glass sheet, but it should be noted that those glass layers may include a glass laminate structure including a glass-polymer laminate structure or a glass-glass laminate structure, and the appended claims should not be so limited. Suitable glass-polymer laminate structures include a single sheet of glass laminated to a polymer film, two glass sheets having an intermediate polymer film, and the like. Suitable glass-glass laminate structures include a structure having an inner glass core and one or two outer glass cladding layers. In some embodiments, the laminate may include two or more glass layers, such as three or more glass layers, and those glass layers are selected from alkaline earth aluminosilicate glass, alkali-free aluminosilicate glass, and soda lime glass. Exemplary glass-glass laminate structures and methods of making the same are described in co-owned U.S. Patent No. 8,007,913, U.S. Patent Application Publication Nos. 2013 / 0015180 and 2013 / 0312459, and International Publication No. 14 / 018838, all of which are hereby incorporated by reference.

[0037] The IGUs disclosed herein may be used in a variety of applications, such as, by way of example, windows, doors, and skylights in buildings and other architectural applications, windows in automobiles and other vehicle applications, windows or display panels in appliances, and display panels in electronic devices. According to various embodiments, one or more LEDs may be optically coupled to at least one edge of the IGU to provide illumination across one or more regions of the IGU. Edge lighting, for example, can provide illumination similar to sunlight, which can be useful, for example, as skylights and sunroofs in various architectural and automotive applications. As previously described, bulk or surface light scattering features can be provided in one or more glass layers of the IGU, which can promote the uniformity of light transmitted through the IGU. Low CTE glass will be more readily laser processed to produce such light scattering features in some embodiments compared to higher CTE glass that may crack or otherwise develop other defects during laser patterning.

[0038] In various non-limiting embodiments, using low CTE glass for a center glass layer, such as a third and / or fourth glass layer, can provide several advantages over conventional IGUs. For example, the low CTE center glass layer may have improved resistance to thermal stress and / or breakage caused by temperature gradients across the IGU. Therefore, the manufacturing cost may be reduced by eliminating the thermal tempering process that would otherwise be used to strengthen a center glass layer made of a conventional glass, such as soda lime glass, having a higher CTE.

[0039] Since thermal tempering of the central glass layer can be avoided, the optical performance of the IGU will be improved, for example, because there is no distortion or birefringence caused by such processing steps. The absence of a thermal tempering process also allows for a thinner central glass layer, which can result in a reduction in the overall thickness and / or mass of the IGU. The reduction in the mass of the IGU can result in cost savings during manufacturing, transportation, installation, maintenance, and / or operation. The reduction in the thickness of the IGU can expand the range of applications of the IGU, which would otherwise be limited by design constraints.

[0040] A thinner low-CTE central layer also allows for a wider sealing gap spacing between the glass layers. A larger volume of insulating gas in the sealing gap spacing can improve the energy efficiency of the IGU. An IGU with a narrow sealing gap spacing will have an increased risk of bending due to the contraction of the gas within the gap. Such bending can result in contact between the outer glass layer and the central glass layer. Such contact is aesthetically undesirable and also allows for direct heat conduction between the glass layers, which is also unacceptable from an energy perspective. Using a thinner low-CTE central glass layer allows for a wider gap and thus reduces the potential risk of bending and / or contact between the glass layers.

[0041] Thermal stress that causes breakage of the glass of the IGU can occur, for example, due to a sudden temperature change in one region of the IGU relative to another region of the IGU. For example, a sudden increase in the external (ambient) temperature compared to the internal temperature, or vice versa, can cause thermal stress in one or more regions of the IGU. On a cold morning, sunlight incident on the window can rapidly increase the temperature of the region of the IGU exposed to that sunlight, while the perimeter of the IGU, for example, located below the window frame, remains cold. Finite element analysis (FEA) modeling indicates that the thermal stress generated in the center glass layer can reach a temperature difference of about 0.62 MPa / °C for conventional soda-lime glass. Under summer conditions (e.g., about 28 °C), the center glass layer can reach a high temperature of 60 °C, creating a large temperature difference of 40 °C between the center glass layer and the outer glass layer. Therefore, the thermal stress generated in the center layer made of soda-lime glass can be about 25 MPa or more.

[0042] Soda-lime glass has a CTE of about 90×10 -7 / °C. In comparison, "Corning" "EAGLE XG" glass has a CTE of 31.7×10 -7 / °C, which is about one-third of the CTE of soda-lime glass. Under the same 40 °C temperature gradient described above, the center layer made of "EAGLE XG" glass experiences only 8.7 MPa of thermal stress and will have a lower risk of breakage without thermal tempering or chemical strengthening.

[0043] Modeling was performed to evaluate the use of low-CTE glass as the center glass layer between two glass layers with a higher CTE in the IGU. The model was a three-layer IGU (length = 1265 mm, width = 989 mm) with an outer glass layer (thickness = 4 mm) made of soda-lime glass, an inner glass layer (thickness = 6 mm) made of soda-lime glass, and a center glass layer (thickness = 0.7 mm) made of "EAGLE XG" glass. The gap between the center glass layer and the inner and outer glass layers was 12 mm wide, filled with argon gas, and sealed with a silicone rubber perimeter seal.

[0044] Referring to FIG. 4, the tensile stress on the "EAGLE XG" central glass layer was modeled at +60 °C to simulate the situation where the soda-lime glass layer expands due to the high temperature. FIG. 5 is a model of the compressive stress on the "EAGLE XG" central glass layer at -40 °C for simulating the situation where the soda-lime glass layer contracts due to the low temperature. FIG. 4 shows that the maximum principal stress on the "EAGLE XG" central glass layer at +60 °C is less than 1 MPa, and FIG. 5 shows that the deflection of the "EAGLE XG" central glass layer is less than 1 mm, indicating that the modeled IGU can appropriately withstand damage, distortion, and / or buckling due to thermal stresses induced by both high and low temperature gradients.

[0045] It will be recognized that various disclosed embodiments may include specific features, elements, or steps described with respect to a particular embodiment. It will also be recognized that a specific feature, element, or step, although described with respect to one particular embodiment, may be interchanged with or combined with alternative embodiments in various combinations or orders not shown in the figures.

[0046] It will also be understood that nouns refer to "at least one" object and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, a reference to an "element" includes, unless the context clearly indicates otherwise, an example having one such "element" or having two or more such "elements". Similarly, "a plurality" or "a series" is intended to indicate two or more, and thus, a "series of elements" or "a plurality of elements" indicates two or more such elements.

[0047] Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, examples include from one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that each of the endpoints of a range is significant both in relation to the other endpoint, and independently of the other endpoint.

[0048] All numerical values recited herein are to be construed as including the word “about,” whether or not explicitly indicated, unless otherwise explicitly indicated. However, it will be further understood that each recited numerical value, whether or not expressed with the word “about,” is also to be considered as being accurately recited. Thus, both “dimensions less than 100 nm” and “dimensions of about less than 100 nm” include embodiments of “dimensions of about less than 100 nm” as well as “dimensions less than 100 nm.”

[0049] Unless otherwise explicitly indicated, it is never intended that any of the methods described herein be construed as requiring that the steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or where no such specific order is otherwise specifically recited in the claim or the specification, no specific order is implied.

[0050] Although various features, elements or steps of particular embodiments may be disclosed using the transitional phrase “comprising,” alternative embodiments are implied that may be described using the transitional phrases “consisting of” or “consisting essentially of.” Thus, for example, alternative embodiments implied by an apparatus comprising A + B + C include embodiments where the apparatus consists of A + B + C, and embodiments where the apparatus consists essentially of A + B + C.

[0051] It will be apparent to those skilled in the art that various modifications and changes can be made to the present disclosure without departing from the spirit and scope of the present disclosure. Since modifications, combinations, partial combinations and variations of the disclosed embodiments including the spirit and substance of the present disclosure will occur to those skilled in the art, the present disclosure should be considered to include all within the scope of the appended claims and their equivalents.

[0052] Hereinafter, preferred embodiments of the present invention will be described item by item.

[0053] Embodiment 1 A first glass layer, A second glass layer, A third glass layer disposed between the first and second glass layers, A first sealed gap interval defined between the first glass layer and the third glass layer, and A second sealed gap interval defined between the second glass layer and the third glass layer, A heat-insulating glass unit including wherein the third glass layer has a coefficient of thermal expansion (CTE) in the temperature range of 0 to 300 °C less than 70×10 -7 / °C and a thickness of about 0.3 mm to about 1.2 mm.

[0054] Embodiment 2 The heat-insulating glass unit according to Embodiment 1, wherein the third glass layer is made of aluminosilicate glass.

[0055] Embodiment 3 The heat-insulating glass unit according to Embodiment 2, wherein the third glass layer is made of alkaline earth aluminosilicate glass or alkali-free aluminosilicate glass.

[0056] Embodiment 4 The heat-insulating glass unit according to Embodiment 1, wherein the third glass layer is made of float-formed glass.

[0057] Embodiment 5 The insulating glass unit according to Embodiment 1, wherein the third glass layer has a thickness of from about 0.5 mm to about 1 mm.

[0058] Embodiment 6 The insulating glass unit according to Embodiment 1, wherein the third glass layer has a thickness of from about 0.6 mm to about 0.9 mm.

[0059] Embodiment 7 The insulating glass unit according to Embodiment 1, wherein at least one of the first and second glass layers has a thickness of more than about 2 mm.

[0060] Embodiment 8 The insulating glass unit according to Embodiment 1, wherein at least one of the first, second, and third glass layers is chemically strengthened or thermally tempered.

[0061] Embodiment 9 The insulating glass unit according to Embodiment 1, wherein at least one of the first, second, and third glass layers is a glass laminate.

[0062] Embodiment 10 The insulating glass unit according to Embodiment 1, wherein at least one of the inner surface of the first glass layer, the inner surface of the second glass layer, or the main surface of the third glass layer is coated with at least one low emissivity coating.

[0063] Embodiment 11 The insulating glass unit according to Embodiment 1, wherein at least one main surface of the third glass layer is at least partially patterned with ink or light scattering features.

[0064] Embodiment 12 The insulating glass unit according to Embodiment 1, wherein at least one of the first sealing gap interval and the second sealing gap interval is filled with at least one type of insulating gas or a mixture thereof with air.

[0065] Embodiment 13 A heat insulating glass unit according to Embodiment 1, further comprising a fourth glass layer disposed between the first glass layer and the second glass layer, and a third hermetic gap interval defined between the third glass layer and the fourth glass layer.

[0066] Embodiment 14 The heat insulating glass unit according to Embodiment 13, wherein the fourth glass layer has a coefficient of thermal expansion (CTE) in the temperature range of 0 to 300 °C of less than 70×10 -7 / °C and a thickness of from about 0.3 mm to about 1.2 mm.

[0067] Embodiment 15 The heat insulating glass unit according to Embodiment 14, wherein the fourth glass layer is made of aluminosilicate glass.

[0068] Embodiment 16 The heat insulating glass unit according to Embodiment 14, wherein the fourth glass layer has a thickness of from about 0.5 mm to about 1 mm.

[0069] Embodiment 17 A first glass layer having a coefficient of thermal expansion CTE1, A second glass layer having a coefficient of thermal expansion CTE2, A third glass layer disposed between the first and second glass layers and having a coefficient of thermal expansion CTE3, A first hermetic gap interval defined between the first glass layer and the third glass layer, and A second hermetic gap interval defined between the second glass layer and the third glass layer, A heat insulating glass unit comprising: A heat insulating glass unit in which, when measured over a temperature range of 0 to 300 °C, at least one of CTE1 > CTE3 or CTE2 > CTE3 holds.

[0070] Embodiment 18 A fourth glass layer disposed between the first glass layer and the second glass layer, and a third hermetic gap interval defined between the third glass layer and the fourth glass layer, the heat insulating glass unit according to embodiment 17, wherein the fourth glass layer has a coefficient of thermal expansion CTE4.

[0071] Embodiment 19 At least one of CTE3 and CTE4 over a temperature range of 0 to 300 °C is less than 70×10 -7 / °C, the heat insulating glass unit according to embodiment 17 or 18.

[0072] Embodiment 20 At least one of the third and fourth glass layers is made of aluminosilicate glass, the heat insulating glass unit according to embodiment 17 or 18.

[0073] Embodiment 21 At least one of the third and fourth glass layers has a thickness of from about 0.3 mm to about 1.2 mm, the heat insulating glass unit according to embodiment 17 or 18.

[0074] Embodiment 22 A first glass layer having a coefficient of thermal expansion CTE1, A second glass layer having a coefficient of thermal expansion CTE2, A third glass layer disposed between the first and second glass layers and having a coefficient of thermal expansion CTE3, A first hermetic gap interval defined between the first glass layer and the third glass layer, and A second hermetic gap interval defined between the second glass layer and the third glass layer, A heat insulating glass unit comprising: Measured over a temperature range of 0 to 300 °C, at least one of CTE1 > CTE3 or CTE2 > CTE3 holds, The third glass layer has a CTE3 of less than 70×10 -7 / °C and a thickness of from 0.3 mm to 1.2 mm, a heat insulating glass unit. Embodiment 23 The insulating glass unit according to embodiment 22, wherein the third glass layer comprises aluminosilicate glass, alkaline earth aluminosilicate glass, or alkali-free aluminosilicate glass. Embodiment 24 The insulating glass unit according to embodiment 22, wherein the third glass layer has a thickness of from about 0.5 mm to about 1 mm. Embodiment 25 The insulating glass unit according to embodiment 22, wherein the third glass layer has a thickness of from about 0.6 mm to about 0.9 mm. Embodiment 26 The insulating glass unit according to embodiment 22, wherein at least one of the first and second glass layers has a thickness of more than about 2 mm. Embodiment 27 The insulating glass unit according to embodiment 22, wherein at least one of the first and second glass layers has a thickness of from 4 mm to 7 mm. Embodiment 28 The insulating glass unit according to embodiment 22, wherein at least one of the first, second, and third glass layers is chemically strengthened or thermally tempered. Embodiment 29 The insulating glass unit according to embodiment 22, wherein at least one of the first, second, and third glass layers is a glass laminate. Embodiment 30 The insulating glass unit according to embodiment 22, wherein at least one of the inner surface of the first glass layer, the inner surface of the second glass layer, or the major surface of the third glass layer is coated with at least one low emissivity coating. Embodiment 31 The insulating glass unit according to embodiment 22, wherein at least one of the first seal gap interval and the second seal gap interval is filled with at least one type of insulating gas or a mixture thereof with air.

Explanation of Signs

[0075] 10 First glass layer 15 First gap interval 16 First coating 18, 28, 38, 48 Sealant assembly 20 Second glass layer 25 Second gap interval 26 Second coating 30 Third glass layer 35 Third gap interval 40 Fourth glass layer 45 Fourth gap interval 55 Cut corner 100, 200 IGU

Claims

【Claim 1】 Coefficient of thermal expansion CTE １ a first glass layer having Coefficient of thermal expansion CTE ２ a second glass layer having Disposed between the first and second glass layers, having a coefficient of thermal expansion CTE ３ a third glass layer having a first hermetic gap interval defined between the first glass layer and the third glass layer, and a second hermetic gap interval defined between the second glass layer and the third glass layer, a heat-insulating glass unit comprising Measured over a temperature range of 0 to 300°C, CTE １ > CTE ３ or CTE ２ > CTE ３ at least one of which holds true, The third glass layer has a CTE of less than 70×10 －７ / °C and a thickness of from 0.3 mm to 1.2 mm, an insulating glass unit. ３ ​

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