Laminate

Abstract

To provide a laminate capable of reducing a phenomenon of a lot of parts of intermediate layer gathering partially.SOLUTION: A glass laminate 1 includes a first glass plate 40A, a second glass plate 40B and an intermediate layer 30 arranged between the first glass plate 40A and the second glass plate 40B, and is composed to have a curved surface. A constant interval is maintained with regard to an interval in a normal direction between opposing faces at which the first glass plate 40A and the second glass plate 40B face each other.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present disclosure relates to a laminate. [Background technology]

[0002] Light-controlling materials have been proposed that can be used as electronic blinds that are installed on windows to control the transmission of external light, etc. One such light-controlling material is a light-control film (liquid crystal film) that uses liquid crystals. A liquid crystal film is made by sandwiching a liquid crystal material between transparent plates containing transparent electrodes, and then sandwiching this between linear polarizers. This light control film changes the orientation of the liquid crystal by changing the electric field applied between the transparent electrodes, thereby controlling the amount of external light transmitted.

[0003] It has also been proposed to produce laminated glass by sandwiching the above-mentioned liquid crystal film between two or more sheets of glass (see Patent Document 1). However, laminated glass sandwiching a liquid crystal film has never been manufactured before, and simply applying the same techniques as for conventional laminated glass, which is constructed by sandwiching an interlayer film, may not be able to properly manufacture the laminated glass sandwiching a liquid crystal film.

[0004] In particular, when the surface shape of the laminated glass is curved or three-dimensional, a phenomenon occurs in which a large amount of liquid crystal gathers locally on the liquid crystal film sandwiched between glass plates with curved or three-dimensional surface shapes (hereinafter referred to as "liquid crystal accumulation"), which can cause the thickness of the liquid crystal film to become uneven.

[0005] Furthermore, not only when a liquid crystal film is sandwiched, but also when an intermediate layer of varying thickness is sandwiched between two pieces of glass, a phenomenon in which the intermediate layer accumulates in large amounts in certain areas can occur. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-144554 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the embodiments of the present disclosure is to provide a laminate that can reduce the phenomenon in which a large amount of a portion of the intermediate layer gathers in a certain area. [Means for solving the problem]

[0008] The embodiments of the present disclosure solve the above-mentioned problems by the following solutions. Note that, for ease of understanding, the following description will be given with reference numerals corresponding to the embodiments of the present disclosure, but the present disclosure is not limited to these.

[0009] The first disclosed embodiment is a laminate (1) having a curved surface, the laminate (1) comprising a first transparent substrate (40A), a second transparent substrate (40B), and an intermediate layer (30) disposed between the first transparent substrate (40A) and the second transparent substrate (40B), wherein the distance in the normal direction between the opposing surfaces of the first transparent substrate (40A) and the second transparent substrate (40B) facing each other is constant.

[0010] A second disclosed embodiment is a laminate (1) according to the first disclosed embodiment, wherein the intermediate layer (30) comprises a first intermediate film (31A), a second intermediate film (31B), and a liquid crystal film (10) disposed between the first intermediate film (31A) and the second intermediate film (31B).

[0011] A third disclosed embodiment is a laminate (1) according to the first or second disclosed embodiment, wherein the surface of the laminate (1) has a curved surface of a three-dimensional shape. [Effects of the Invention]

[0012] According to an embodiment of the present disclosure, a laminate can be provided that can reduce the phenomenon in which a large amount of part of the intermediate layer gathers in certain areas. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates a laminated glass 1 according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is an exploded view showing the layer structure of a laminated glass 1. [Figure 3] 1 is a cross-sectional view mainly showing a light control film 10 in the layer structure of laminated glass 1 according to an embodiment of the present disclosure. [Figure 4] 2 is a cross-sectional view of the laminated glass 1 taken along the arrow AA in FIG. 1. [Figure 5] FIG. 5 is a cross-sectional view showing FIG. 4 with the intermediate layer 30 omitted. [Figure 6] FIG. 1 is a diagram showing a state in which two glass plates are stacked together and formed into a desired shape. [Figure 7] FIG. 7 is a diagram showing a state in which an intermediate layer 30 is sandwiched between glass plates formed by the method shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0014] Best modes for carrying out embodiments of the present disclosure will be described below with reference to the drawings and the like.

[0015] (First embodiment) FIG. 1 is a diagram showing a laminated glass 1 according to an embodiment of the present disclosure. FIG. 2 is an exploded view showing the layer structure of the laminated glass 1. As shown in FIG. Note that the drawings shown below, including FIGS. 1 and 2, are schematic diagrams, and the size and shape of each part are exaggerated as appropriate to facilitate understanding. In the following description, specific numerical values, shapes, materials, etc. are given, but these can be changed as appropriate. In the embodiments of the present disclosure, terms specifying shapes or geometric conditions, such as parallel and orthogonal, are intended to include not only their strict meanings but also states that perform similar optical functions and have an error that can be considered as parallel or orthogonal.

[0016] In the embodiments of the present disclosure, the terms plate, sheet, film, etc. are used, but in general, these are used in order of thickness, that is, plate, sheet, film, and so on, and this specification follows suit. However, since there is no technical meaning in this distinction, these terms can be used interchangeably as appropriate.

[0017] In the embodiments of the present disclosure, the term "transparent" refers to a material that transmits at least light of a wavelength to be used. For example, even if a material does not transmit visible light, if it transmits infrared light, it is treated as transparent when used in infrared applications. It should be noted that the specific numerical values specified in this specification and claims should be treated as including a general error range. In other words, a difference of about ±10% is not substantially different, and numerical values set in a range slightly exceeding the numerical range of this application should be interpreted as being substantially within the scope of the embodiments of the present disclosure.

[0018] The surface of the laminated glass 1, which is a laminate, has a three-dimensional curved surface. Here, the three-dimensional curved surface is not a simple cylindrical surface, but a curved surface that cannot be constructed by simply deforming a plane without expansion or contraction, and is a curved surface defined by two independent parameters in three-dimensional space. For example, an example of a curved surface is one having two curvature criteria as parameters, with orthogonal X-axis and Y-axis as central axes, respectively, being a radius of curvature Rx centered on the X-axis and a radius of curvature Ry centered on the Y-axis. In the embodiments of the present disclosure, for ease of understanding, the surface shape of the laminated glass 1 will be described as being part of a spherical shape.

[0019] The laminated glass 1 according to the embodiment of the present disclosure is configured by sandwiching an interlayer 30 between a first glass plate (first transparent substrate) 40A and a second glass plate (second transparent substrate) 40B. More specifically, the laminated glass 1 includes the first glass plate 40A, a first interlayer 31A, a light control film (liquid crystal film) 10, a second interlayer 31B, and a second glass plate 40B, stacked in this order. In the laminated glass 1 according to the embodiment of the present disclosure, the first interlayer 31A, the light control film (liquid crystal film) 10, and the second interlayer 31B are combined to form the interlayer 30.

[0020] (Basic structure of light-control film) Fig. 3 is a cross-sectional view mainly showing the light control film 10 in the layer structure of the laminated glass 1 according to an embodiment of the present disclosure. Although the laminated glass 1 according to an embodiment of the present disclosure has a three-dimensional surface shape, Fig. 3 shows a cross-sectional view of the surface shape when it is planar for ease of understanding. The specific structure of the light control film 10 described below is an example, and the structure of each part can be changed as appropriate. The light control film (liquid crystal film) 10 is a film that can control the amount of transmitted light by changing the applied voltage. The light control film 10 of the embodiment of the present disclosure is used by being sandwiched between glass plates (transparent members) together with or instead of the intermediate material of the laminated glass 1. The laminated glass 1 equipped with this light-controlling film 10 is placed in areas where light control is required (areas where external light enters, such as front, side, rear, or roof windows), such as window glass in buildings, showcases, indoor transparent partitions, and vehicle windows, and can control the amount of light entering the inside of buildings, vehicles, etc.

[0021] The light control film 10 (liquid crystal film) is a component that has a guest-host type liquid crystal layer that uses a dichroic dye and changes the amount of light transmitted by an electric field applied to the liquid crystal. The light control film 10 is constructed by sandwiching a liquid crystal layer 14 between a film-like first laminate 12 and a film-like second laminate 13. The first laminate 12 is formed by laminating a transparent electrode 22A and an alignment film layer 23A on a first base material 21A. The second laminate 13 is formed by laminating a transparent electrode 22B, an alignment film layer 23B, and bead spacers 24 on a second substrate 21B. The light-controlling film 10 changes the orientation of the liquid crystal material consisting of a guest-host liquid crystal composition provided in the liquid crystal layer 14 by driving the transparent electrodes 22A and 22B provided in the first laminate 12 and the second laminate 13, thereby changing the amount of transmitted light.

[0022] The first base material 21A and the second base material 21B are made of a transparent resin, and a flexible film can be used. As the first base material 21A and the second base material 21B, it is desirable to use a transparent resin film that has small optical anisotropy and a transmittance of 80% or more in the visible wavelength range (400 to 800 nm). When the light control film 10 according to the embodiment of the present disclosure is laminated with glass, its surface is deformed to have a three-dimensional curved shape, and therefore, the transparent resin film material used for the first substrate 21A and the second substrate 21B is preferably made of one of polycarbonate (PC) resin, polyethylene terephthalate (PET) resin, and cycloolefin polymer (COP) resin. Furthermore, the thickness of the first substrate 21A and the second substrate 21B is preferably 150 μm or less.

[0023] The transparent electrodes 22A and 22B are made of transparent conductive films laminated on the first substrate 21A and the second substrate 21B (transparent resin film). The transparent conductive film can be made of various transparent electrode materials that are used for this type of transparent resin film, including oxide-based transparent metal thin films with a total light transmittance of 50% or more, such as tin oxide, indium oxide, zinc oxide, and silver nanowires (AgNW).

[0024] Examples of tin oxide (SnO2) based materials include NESA (tin oxide SnO2), ATO (antimony tin oxide: antimony-doped tin oxide), and fluorine-doped tin oxide. Examples of indium oxide (In2O3) based materials include indium oxide, ITO (Indium Tin Oxide), and IZO (Indium Zinc Oxide). Zinc oxide (ZnO) based materials include zinc oxide, AZO (aluminum-doped zinc oxide), and gallium-doped zinc oxide. In the embodiment of the present disclosure, the transparent conductive films that form the transparent electrodes 22A and 22B are made of ITO.

[0025] In the embodiment of the present disclosure, the spacers used are spherical bead spacers 24. The bead spacers 24 are provided to define the thickness (cell gap) of the liquid crystal layer 14 except for the outer periphery. The bead spacers 24 can be made of a wide variety of materials, including inorganic materials such as silica, organic materials, and core-shell structures that combine these materials. In addition to spherical shapes, the bead spacers 24 may also be made in rod shapes such as cylindrical or prismatic shapes. However, the spacers that define the thickness of the liquid crystal layer 14 are not limited to the bead spacers 24, and may be formed into a cylindrical shape by applying a photoresist to the first base material 21A side, exposing it to light, and developing it. In the above explanation, an example was shown in which such a spacer is provided in the second stack 13, but this is not limited to this, and the spacer may be provided in both the first stack 12 and the second stack 13, or only in the first stack 12.

[0026] The alignment film layers 23A and 23B are films for aligning liquid crystal molecules in a certain direction. For example, the alignment film layers 23A and 23B may be fabricated as photo-alignment film layers, or may be fabricated by rubbing instead of photo-alignment film layers, or may be fabricated by forming fine linear concave and convex shapes. The fabrication method for the alignment film layers 23A and 23B is not limited to the above-described method, and other suitable methods may be used. Furthermore, in the embodiment of the present disclosure, the light control film 10 has been shown to have the alignment film layers 23A and 23B, but is not limited to this, and may have a configuration that does not have the alignment film layers 23A and 23B.

[0027] A wide variety of guest-host liquid crystal compositions using a dichroic dye composition can be used for the liquid crystal layer (liquid crystal material) 14. The guest-host liquid crystal composition may contain a chiral agent so that when the liquid crystal material is horizontally aligned, it is helically aligned in the thickness direction of the liquid crystal layer 14. In the light control film 10, a sealant 25 is disposed so as to surround the periphery of the liquid crystal layer 14 in a planar view. This sealant 25 holds the first laminate 12 and the second laminate 13 together and prevents leakage of the liquid crystal material of the liquid crystal layer 14. The sealant 25 can be, for example, a thermosetting resin such as an epoxy resin or an acrylic resin, or an ultraviolet-curable resin.

[0028] The light control film 10 is configured as a normally clear film by configuring the alignment film layers 23A and 23B as vertical alignment film layers in which an alignment restraining force related to the pretilt is set in a certain direction so that the alignment of the guest-host liquid crystal composition during this light-shielding state is the same as that during an applied electric field. Note that the light-transmitting state may also be configured as a normally dark state by configuring the light-transmitting state as that during an applied electric field. Normally dark is a structure in which the transmittance is at its minimum when no voltage is applied to the liquid crystal, resulting in a black screen, whereas normally clear is a structure in which the transmittance is at its maximum when no voltage is applied to the liquid crystal, resulting in a transparent screen.

[0029] Although the light control film 10 of the embodiment of the present disclosure has been shown as having a guest-host liquid crystal layer 14, it may also be configured to have a liquid crystal layer 14 of a TN (Twisted Nematic) type, a VA (Vertical Alignment) type, an IPS (In-Plane-Switching) type, or the like that does not use a dichroic dye composition. When such a liquid crystal layer 14 is provided, it can function as a light control film by further providing linear polarization layers on the surfaces of the first substrate 21A and the second substrate 21B.

[0030] The first glass plate 40A and the second glass plate 40B are disposed on the front and back surfaces of the laminated glass 1, respectively, and are highly translucent glass plates. In the embodiment of the present disclosure, the first glass plate 40A and the second glass plate 40B are both made of glass plates having a thickness of 2 mm. The first glass plate 40A and the second glass plate 40B are pre-formed so that their surfaces have three-dimensional curved shapes. The shapes of the first glass plate 40A and the second glass plate 40B will be described in detail later.

[0031] In the embodiment of the present disclosure, the first interlayer film 31A and the second interlayer film 31B are 760 μm thick sheets made of PVB (polyvinyl butyral) resin. The first interlayer film 31A bonds the first glass plate 40A and the light control film 10, and similarly, the second interlayer film 31B bonds the second glass plate 40B and the light control film 10. The first intermediate film 31A and the second intermediate film 31B may be made of EVA (ethylene-vinyl acetate copolymer), COP (cycloolefin polymer), or the like. The Tg of the first interlayer 31A and the second interlayer 31B is 70 to 90°C when PVB is used, -30°C (melting point: 75°C) when EVA is used, and 100 to 120°C when COP is used. The thickness of the first intermediate film 31A and the second intermediate film 31B may also be selected appropriately depending on the material and the like.

[0032] FIG. 4 is a cross-sectional view of the laminated glass 1 taken along the arrow AA in FIG. FIG. 5 is a cross-sectional view showing the structure of FIG. 4 with the intermediate layer 30 omitted. As described above, in the embodiment of the present disclosure, the surface shape of the laminated glass 1 is a part of a spherical shape. Therefore, in Figures 4 and 5, the surface of the laminated glass 1 is an arc in cross section, and the surface of the convex side of the first glass plate 40A is also an arc in cross section. Furthermore, because the thickness of the first glass plate 40A is constant at 2 mm, the surface of the first glass plate 40A on the side that is bonded to the interlayer 30 (the concave side) is also an arc in cross section.

[0033] As shown in FIGS. 4 and 5, RA denotes the radius of the arc of the first glass sheet 40A on the side bonded to the interlayer 30. RB denotes the radius of the arc of the cross-sectional shape of the surface of the second glass sheet 40B on the side bonded to the interlayer 30. The state shown in FIG. 5 is a state in which the interlayer 30 has been virtually removed from the laminated glass 1. The first glass sheet 40A and the second glass sheet 40B are shaped so that the distance in the normal direction between the opposing surfaces of the first glass sheet 40A and the second glass sheet 40B is a constant distance, RA - RB = t30. Therefore, even when the laminated glass is formed with the interlayer 30 sandwiched between them as shown in FIG. 4, the distance in the normal direction between the opposing surfaces of the first glass sheet 40A and the second glass sheet 40B is a constant distance, RA - RB = t30. Naturally, the thickness of the interlayer 30 in the laminated glass state is also a constant distance, t30.

[0034] Here, a difference between the gap between the first glass plate 40A and the second glass plate 40B in the embodiment of the present disclosure and the conventional gap will be described. Conventionally, the simplest configuration for curved laminated glass is one in which an interlayer is sandwiched between two identically curved glass sheets. However, in such a configuration, the radius of the arc on the convex surface of the glass sheets is larger than the radius of the arc on the concave surface of the glass sheets by the thickness of the glass sheets. This means that the interlayer is disposed between surfaces whose arc dimensions differ by the thickness of the glass sheets. In this case, as illustrated, the gap between the two glass sheets varies depending on the location. In particular, the gap is narrower at the periphery than near the center of the glass sheets. As a result, when the glass is laminated, the pressure pressing the interlayer at the periphery is higher than at the center, resulting in a phenomenon in which the interlayer accumulates in a larger amount at the periphery. In particular, when the interlayer contains a liquid crystal film, liquid crystal accumulation can occur at the periphery.

[0035] Therefore, when forming a glass sheet into a curved surface, two glass sheets are stacked and formed into the desired shape in advance, which allows the shapes of the opposing surfaces that sandwich the interlayer to be closer to the appropriate shape when the glass sheet is formed into a laminated glass. FIG. 6 is a diagram showing a state in which two glass plates are stacked together and formed into a desired shape. FIG. 7 is a diagram showing a state in which the intermediate layer 30 is sandwiched between glass plates formed by the method shown in FIG. In the conventional glass panels shown in FIGS. 6 and 7, the radius of the arc of the surface where the first glass plate 400A and the second glass plate 400B face each other is RC. In this case, even in the state shown in FIG. 7 where the interlayer 30 is sandwiched between the glass panels to form a laminate, the radius of the arc of the surface where the first glass plate 400A and the second glass plate 400B face each other is RC, and the centers of the arcs are offset. Therefore, in the laminated glass shown in FIG. 7, the gap between the first glass plate 400A and the second glass plate 400B is narrower at the periphery than near the center of the laminated glass. This is particularly noticeable when the interlayer 30 is thick. For example, the light control film 10 according to the present disclosure has a thickness of 2.4 mm, which results in an uneven gap between the first glass plate 400A and the second glass plate 400B, which can cause liquid crystal accumulation in the periphery.

[0036] Here, we investigated how much the distance t30 in the normal direction between the opposing surfaces of the first glass plate 40A and the second glass plate 40B needs to change to cause liquid crystal accumulation. Specifically, we produced prototype laminated glass with different distances between the center of the glass (hereinafter referred to as t30A) and the edge of the glass (hereinafter referred to as t30B), and investigated the occurrence of liquid crystal accumulation. The dimensions of the laminated glass were 262 mm (in the cross-sectional direction of FIG. 5) × 328 mm, with RA (design target value) = 1698.4 mm, and the thickness of the first glass plate 40A and the second glass plate 40B themselves was 2 mm.

[0037] (Prototype 1) For prototype 1, the distance between the center of the glass (t30A) was 2.4 mm, and the distance between the edges of the glass (t30B) was 2.387 mm. Therefore, the difference in t30 (Δt) was 0.013 mm (t30A-t30B). This is 0.54% of the target t30 value of 2.4 mm. In this prototype 1, accumulation of liquid crystal was confirmed. (Prototype 2) For prototype 2, the distance between the center of the glass (t30A) was 2.4 mm, and the distance between the edges of the glass (t30B) was 2.393 mm. Therefore, the difference in t30 (Δt) was 0.007 mm (t30A-t30B). This is 0.3% of the target t30 value of 2.4 mm. In this prototype 2, no liquid crystal accumulation occurred. From the above results, it is preferable that the dimensional difference (dimensional variation) of t30 is within 0.3%, since this can prevent the occurrence of liquid crystal accumulation.

[0038] In this way, in the conventional configuration, the pressure pressing the intermediate layer in the peripheral area is higher than in the central area, causing the intermediate layer to partially collect in the peripheral area. In particular, when the intermediate layer includes a liquid crystal film, liquid crystal accumulation can occur in the peripheral area. In contrast, in the embodiment of the present disclosure, the distance t30 between the opposing surfaces of the first glass plate 40A and the second glass plate 40B in the normal direction is a constant distance. More specifically, t30 is a constant distance of 2.4 mm. This prevents the phenomenon of excessive accumulation of the intermediate layer in the peripheral area, which has occurred in conventional laminated glass. In particular, since the intermediate layer 30 contains the light control film 10, accumulation of liquid crystals in the peripheral area can be prevented.

[0039] (Variations) The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible, and these are also within the scope of the embodiments of the present disclosure.

[0040] (1) In the embodiment, an example has been described in which the intermediate layer 30 includes a liquid crystal film, but the present invention is not limited to this, and for example, the intermediate layer may be configured not to include a liquid crystal film.

[0041] (2) In the embodiment, the laminated glass 1 has been described as having a surface that is part of a spherical shape. However, the curved surface of the laminated glass may have a more complex, hair-like shape, such as a continuous wavy uneven shape, and the three-dimensional curved surface may have various shapes. Conversely, the shape is not limited to a three-dimensional shape, and may also be a simple curved surface such as a cylindrical surface.

[0042] (3) In the embodiment, a laminated glass using glass plates as the first transparent substrate and the second transparent substrate has been described as an example of the laminate. However, the laminate is not limited to this, and may be one using transparent resin substrates as the first transparent substrate and the second transparent substrate.

[0043] The embodiments and modifications may be used in combination as appropriate, but detailed description thereof will be omitted. The embodiments of the present disclosure are not limited to the embodiments described above. [Explanation of symbols]

[0044] 1. Laminated glass 10. Light control film (liquid crystal film) 12 First laminate 13 Second laminate 14 Liquid crystal layer 21A First substrate 21B Second substrate 22A transparent electrode 22B Transparent electrode 23A Alignment layer 23B Alignment layer 24 Bead Spacer 25 Sealing material 30 Middle Class 31A First Interlayer 31B Second interlayer 40A First Glass Plate 40B Second glass plate

Claims

1. a first transparent substrate; A second transparent substrate; an intermediate layer disposed between the first transparent substrate and the second transparent substrate; Equipped with A laminate configured on a curved surface, The intermediate layer is a first interlayer film; and a second interlayer film; and a liquid crystal film disposed between the first interlayer film and the second interlayer film; Equipped with The liquid crystal film is a first substrate; a second substrate; and a liquid crystal layer disposed between the first substrate and the second substrate; Equipped with a distance in a normal direction between opposing surfaces of the first transparent substrate and the second transparent substrate is constant; A laminate in which the dimensional difference between the spacing at the center and the spacing at the end portions is within 0.3% based on the spacing at the center.

2. The laminate according to claim 1 , The surface of the laminate has a curved surface having a three-dimensional shape.

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