Laminated glass

Abstract

Provided is laminated glass comprising a light-absorbing intermediate layer and being capable of successfully propagating light inside the laminated glass. The laminated glass according to the present disclosure comprises: a first glass plate (11) having a first main surface (21) and a second main surface (22); a second glass plate (12) having a third main surface (23) and a fourth main surface (24); a light-absorbing intermediate layer (13) disposed between the first glass plate (11) and the second glass plate (12); and a light scattering region (15) disposed so as to be closer to the fourth main surface (24) side than the light-absorbing intermediate layer (13). The light scattering region (15) scatters light (31) incident from a light source to the fourth main surface (24) side. The refractive index difference between the light-absorbing intermediate layer (13) and a member in contact with the light-absorbing intermediate layer (13) on the fourth main surface (24) side is 0.05 or more. The visible light reflectance measured from the fourth main surface (24) side is 15% or less. The visible light transmittance measured from the fourth main surface (24) side in a region other than the light scattering region (15) is 30% or less.

Description

Laminated glass

[0001] The present disclosure relates to laminated glass.

[0002] Laminated glass, which is formed by bonding two glass sheets together using an interlayer, is used in windows of vehicles and buildings. Recently, a technology has been developed in which light is introduced into the interior of the laminated glass from an edge of the laminated glass using a light source such as a light-emitting diode (LED), and the light is extracted to the outside of the laminated glass using a scattering layer provided on the laminated glass.

[0003] Patent Document 1 discloses a technology relating to vehicle glazing in which an LED is disposed on the edge surface of a glass sheet on the interior side of a vehicle, and the LED emits light by guiding it through the laminated glass.

[0004] Special table 2017-504938 publication

[0005] As described above, a technology has been developed in which irradiated light is introduced into the interior of the laminated glass from the edge of the laminated glass using a light source such as an LED, and the light is extracted to the exterior of the laminated glass using a scattering layer provided on the laminated glass. On the other hand, some laminated glasses use a light-absorbing interlayer as an intermediate layer in order to reduce the proportion of sunlight that enters the vehicle from the outside. When irradiated light is introduced into such laminated glass having a light-absorbing interlayer using an LED or the like, there is a problem in that the introduced irradiated light is absorbed by the light-absorbing interlayer, and the irradiated light does not propagate far inside the laminated glass.

[0006] In view of the above problems, an object of the present disclosure is to provide laminated glass that includes a light-absorbing interlayer and allows light to propagate well inside the laminated glass.

[0007] A laminated glass according to one aspect of the present disclosure is as follows: [1] A laminated glass comprising: a first glass plate having a first main surface and a second main surface; a second glass plate having a third main surface and a fourth main surface; a light-absorbing intermediate layer disposed between the first glass plate and the second glass plate; and a light-scattering region disposed on the fourth main surface side of the light-absorbing intermediate layer, wherein the second main surface and the third main surface face each other, the light-scattering region scatters light incident from a light source toward the fourth main surface side, the refractive index difference between the light-absorbing intermediate layer and a member in contact with the light-absorbing intermediate layer on the fourth main surface side is 0.05 or more, the visible light reflectance measured from the fourth main surface side is 15% or less, and the visible light transmittance measured from the fourth main surface side in a region other than the light-scattering region is 30% or less.

[0008] [2] The laminated glass according to [1], wherein the member in contact with the light-absorbing intermediate layer on the fourth main surface side is a low-refractive-index intermediate layer.

[0009] [3] The laminated glass according to [1], wherein the member in contact with the light-absorbing intermediate layer on the fourth main surface side is the second glass plate.

[0010] [4] The laminated glass according to [2], wherein the low refractive index intermediate layer contains at least one selected from the group consisting of polyvinyl butyral resin, ethylene vinyl acetate copolymer resin, polyurethane resin, ionomer resin, and cycloolefin polymer, or an acrylic, silicone, epoxy, or urethane acrylate optical adhesive material.

[0011] [5] The laminated glass according to any one of [1] to [4], wherein the light-absorbing intermediate layer contains at least one resin selected from the group consisting of a polyvinyl butyral resin, an ethylene-vinyl acetate copolymer resin, a polyurethane resin, an ionomer resin, and a cycloolefin polymer.

[0012] [6] The laminated glass according to any one of [1] to [5], wherein the light-absorbing intermediate layer has a visible light transmittance of 30% or less.

[0013] [7] The laminated glass according to any one of [1] to [6], wherein the light-absorbing intermediate layer is made of a resin material containing a dye.

[0014] [8] The laminated glass according to any one of [1] to [7], wherein the refractive index difference at a wavelength of 630 nm is 0.05 or more.

[0015] [9] The laminated glass according to any one of [1] to [8], wherein the second glass plate has a visible light transmittance of 85% or more.

[0016]

[10] The laminated glass according to any one of [1] to [9], wherein the light-scattering region is formed on the third main surface of the second glass plate or on the surface of the light-absorbing intermediate layer facing the fourth main surface.

[0017]

[11] The laminated glass according to any one of [1] to

[10] , wherein the refractive index difference is 0.2 or less.

[0018]

[12] The laminated glass according to any one of [1] to

[11] , wherein the visible light reflectance measured from the fourth main surface side is 3% or more.

[0019] The present disclosure makes it possible to provide laminated glass that includes a light-absorbing interlayer and allows light to propagate well inside the laminated glass.

[0020] Fig. 1 is a cross-sectional view illustrating a configuration example of laminated glass according to embodiment 1. Fig. 2 is a cross-sectional view illustrating a configuration example of laminated glass according to embodiment 2. Fig. 3 is a cross-sectional view illustrating a configuration example of laminated glass according to embodiment 3.

[0021] Summary of the Disclosure A laminated glass according to the disclosure includes a first glass plate having a first principal surface and a second principal surface, a second glass plate having a third principal surface and a fourth principal surface, a light-absorbing intermediate layer disposed between the first glass plate and the second glass plate, and a light-scattering region disposed closer to the fourth principal surface than the light-absorbing intermediate layer. The light-scattering region scatters light incident from a light source toward the fourth principal surface. The difference in refractive index between the light-absorbing intermediate layer and a member in contact with the light-absorbing intermediate layer on the fourth principal surface side is 0.05 or more, the visible light reflectance measured from the fourth principal surface side is 15% or less, and the visible light transmittance measured from the fourth principal surface side in a region other than the light-scattering region is 30% or less.

[0022] In one embodiment of the present disclosure, the member in contact with the light absorbing intermediate layer on the fourth principal surface side is a low refractive index intermediate layer, and the configuration in this case corresponds to the configuration shown in FIGS. 1 and 2 of the present application.

[0023] In another embodiment of the present disclosure, the member in contact with the light absorbing intermediate layer on the fourth major surface side is a second glass plate, and the configuration in this case corresponds to the configuration shown in FIG. 3 of the present application.

[0024] The specific configuration of the laminated glass according to the present disclosure will be described in detail below.

[0025] <First Embodiment> Fig. 1 is a cross-sectional view illustrating an example of the configuration of laminated glass according to the first embodiment. As shown in Fig. 1 , laminated glass 1a according to the present embodiment includes a first glass plate 11 having a first main surface 21 and a second main surface 22, a second glass plate 12 having a third main surface 23 and a fourth main surface 24, a light-absorbing intermediate layer 13 and a low-refractive-index intermediate layer 14 disposed between first glass plate 11 and second glass plate 12, and a light-scattering region 15 disposed on the fourth main surface 24 side of low-refractive-index intermediate layer 14. The second main surface 22 of first glass plate 11 and the third main surface 23 of second glass plate 12 are disposed so as to face each other. Furthermore, light-absorbing intermediate layer 13, low-refractive-index intermediate layer 14, and light-scattering region 15 are disposed so as to be sandwiched between second main surface 22 of first glass plate 11 and third main surface 23 of second glass plate 12.

[0026] The laminated glass 1a according to this embodiment can be used, for example, as a vehicle window. Examples of vehicle windows include roof glass, windshields, rear windows, side windows, and inset windows. The laminated glass 1a is suitable for vehicle roof glass, rear windows, rear side windows, and inset windows, and is particularly suitable for roof glass.

[0027] The laminated glass 1a according to this embodiment may be flat or curved. It may also have a shape including both flat and curved surfaces. The first glass sheet 11 and the second glass sheet 12 may each be flat or curved. However, it is preferable that at least one of them is curved, as this makes it easier to ensure the strength of the laminated glass, and it is even more preferable that both are curved. The curved sheet may have a single curved shape curved in one direction, or a three-dimensional shape curved in two or more directions. The three-dimensional shape may be, for example, a complex curved shape curved in two orthogonal directions. In the following example, a case will be described in which both the first glass sheet 11 and the second glass sheet 12 are flat, but the same explanation can be applied to the case in which at least one of them is curved.

[0028] The outer edge shape of the first glass plate 11 and the second glass plate 12 in a plan view may be any shape, but is preferably, for example, rectangular, trapezoidal, or triangular.

[0029] The first glass plate 11 includes a first major surface 21 opposite to the light absorbing intermediate layer 13 and a second major surface 22 facing the light absorbing intermediate layer 13. The second glass plate 12 includes a third major surface 23 facing the low refractive index intermediate layer 14 and a fourth major surface 24 facing the low refractive index intermediate layer 14. For example, the first major surface 21 of the first glass plate 11 is disposed on the exterior side of the vehicle, and the fourth major surface 24 of the second glass plate 12 is disposed on the interior side of the vehicle.

[0030] The first and second glass plates 11, 12 may be made of, for example, transparent inorganic glass. For example, soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, or the like may also be used for the first and second glass plates 11, 12. Alternatively, the first and second glass plates 11, 12 may be made of organic glass (resin). Examples of organic glass that may be used include polycarbonate resin, polystyrene resin, aromatic polyester resin, acrylic resin, polyester resin, polyarylate resin, polycondensation product of halogenated bisphenol A and ethylene glycol, acrylic urethane resin, and halogenated aryl group-containing acrylic resin.

[0031] The thickness of each of the first and second glass sheets 11, 12 is, for example, 0.1 mm to 10 mm, and from the viewpoint of resistance to stone chipping, is preferably 0.3 mm to 3.0 mm, more preferably 1.1 mm to 2.6 mm, and even more preferably 1.7 mm to 2.1 mm. The thicknesses of the first and second glass sheets 11, 12 may be the same or different. For example, the thickness of the first glass sheet 11 located on the vehicle exterior side may be thicker than the thickness of the second glass sheet 12 located on the vehicle interior side. In this way, if the thickness of the first glass sheet 11 located on the vehicle exterior side is thicker, the strength of the laminated glass 1a against objects flying toward the laminated glass 1a is improved.

[0032] The light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14 are sandwiched between the second main surface 22 of the first glass plate 11 and the third main surface 23 of the second glass plate 12. In other words, the first glass plate 11 and the second glass plate 12 are bonded together using the light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14. Specifically, when forming the laminated glass 1a, the first glass plate 11, the light-absorbing intermediate layer 13, the low-refractive-index intermediate layer 14, and the second glass plate 12 are laminated in this order, and the laminate is then heated and pressurized to form a laminated glass 1a. The light-scattering region (scattering layer) 15 may be formed on the main surface of the low-refractive-index intermediate layer 14 or the main surface of the second glass plate 12 so as to be located between the low-refractive-index intermediate layer 14 and the second glass plate 12, for example, or may be disposed between the low-refractive-index intermediate layer 14 and the second glass plate 12 as a member independent of the low-refractive-index intermediate layer 14 and the second glass plate 12. The light-scattering region (scattering layer) 15 has a light-scattering pattern formed therein, and the non-light-scattering region 16 has the low-refractive-index intermediate layer 14 in direct contact with the third main surface 23 of the second glass plate 12. The total area of ​​the portion where the light-scattering pattern is formed is, for example, less than 50%, preferably 40% or less, and more preferably 30% or less of the area where the first glass plate 11 and the second glass plate 12 overlap in a plan view. Therefore, the adhesive strength between the first glass plate 11 and the second glass plate 12 is ensured.

[0033] The light-absorbing intermediate layer 13 is provided between the first glass plate 11 and the low-refractive-index intermediate layer 14. The light-absorbing intermediate layer 13 is an intermediate layer that has a light-absorbing function. By using the light-absorbing intermediate layer 13 as an intermediate layer of the laminated glass 1a, the proportion of sunlight that enters the vehicle from the outside can be reduced. In other words, the light-absorbing intermediate layer 13 is an intermediate layer that has light-blocking properties. The visible light transmittance of the light-absorbing intermediate layer 13 is preferably 30% or less, more preferably 20% or less, and even more preferably 15% or less. The refractive index of the light-absorbing intermediate layer 13 is preferably 1.30 or more and 1.50 or less, more preferably 1.35 or more and 1.45 or less. Hereinafter, unless otherwise specified, the refractive index is a value at 25°C. The thickness of the light-absorbing intermediate layer 13 is not particularly limited, but is preferably 1.60 mm or less. The thickness of the light absorbing intermediate layer 13 is preferably 0.36 mm or more, and may be 0.50 mm or more, 0.76 mm or more, or 0.80 mm or more.

[0034] The light-absorbing intermediate layer 13 may be made of a resin material containing a dye. The dye may be a pigment or the like. The resin material constituting the light-absorbing intermediate layer 13 may be at least one selected from the group consisting of polyvinyl butyral resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, ionomer resin, and cycloolefin polymer.

[0035] The low-refractive-index intermediate layer 14 is provided between the light-absorbing intermediate layer 13 and the light-scattering region 15 (second glass plate 12). The low-refractive-index intermediate layer 14 is an intermediate layer having a refractive index lower than that of the light-absorbing intermediate layer 13. The low-refractive-index intermediate layer 14 is typically transparent, but may be colored any color. The refractive index of the low-refractive-index intermediate layer 14 is preferably 1.30 or more and 1.50 or less, and more preferably 1.35 or more and 1.45 or less. The thickness of the low-refractive-index intermediate layer 14 is not particularly limited, but is preferably 1.60 mm or less. The thickness of the low-refractive-index intermediate layer 14 is preferably 0.10 mm or more, and may be 0.15 mm or more, 0.36 mm or more, 0.50 mm or more, 0.76 mm or more, or 0.80 mm or more.

[0036] The low-refractive index intermediate layer 14 can be formed using, for example, a thermoplastic resin. Specifically, the low-refractive index intermediate layer 14 can be formed using at least one resin material selected from the group consisting of polyvinyl butyral resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, ionomer resin, and cycloolefin polymer. The low-refractive index intermediate layer 14 may also be formed using an acrylic, silicone, epoxy, or urethane acrylate optical clear adhesive (OCA). The low-refractive index intermediate layer 14 preferably further contains a plasticizer. Examples of plasticizers that can be used include known compounds contained in resin films for conventional laminated glass, such as dihexyl adipate (DHA), triethylene glycol di-2-ethylhexanoate (3GO), tetraethylene glycol di-2-ethylhexanoate (4GO), and triethylene glycol di-2-ethylbutyrate (3GH).

[0037] The refractive index of the low-refractive index intermediate layer 14 can be adjusted, for example, by changing the plasticizer content relative to the thermoplastic resin. For example, as described in Japanese Patent Laid-Open No. 6-273327, a calibration curve showing the relationship between refractive index and plasticizer content can be created by preparing multiple resin films with known plasticizer contents and measuring the refractive index of the resin films with an Abbe refractometer. Using this calibration curve, the information necessary to fabricate a low-refractive index intermediate layer 14 with a desired refractive index can be obtained. However, adjusting the refractive index of the low-refractive index intermediate layer 14 is not limited to adjusting the amount of plasticizer; it can also be achieved, for example, by changing the crystallinity of the resin contained in the low-refractive index intermediate layer 14. Furthermore, when the low-refractive index intermediate layer 14 is made of a polyvinyl butyral resin, the refractive index can also be lowered by increasing the proportion of acetyl groups.

[0038] The total thickness of the light absorbing intermediate layer 13 and the low refractive index intermediate layer 14 is preferably 0.76 mm or more and 2.00 mm or less. The light absorbing intermediate layer 13 and the low refractive index intermediate layer 14 may be configured to contain a common resin material.

[0039] In this embodiment, the refractive index difference between the light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14 is preferably 0.05 or more, more preferably 0.07 or more, and even more preferably 0.09 or more. Furthermore, the refractive index difference between the light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14 is preferably 0.2 or less, more preferably 0.15 or less. If the refractive index difference exceeds 0.2, optical distortion will occur unless the interface between the two layers has a high degree of smoothness, which will pose significant difficulties in terms of both molding and lamination techniques. By setting the refractive index difference between the light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14 within this range, the amount of light incident from the low-refractive-index intermediate layer 14 to the light-absorbing intermediate layer 13 can be reduced. Therefore, the amount of light absorbed by the light-absorbing intermediate layer 13 can be reduced, allowing light to propagate farther within the laminated glass.

[0040] In this embodiment, the refractive index difference at a wavelength of 630 nm is preferably 0.05 or more, more preferably 0.06 or more, even more preferably 0.07 or more, and even more preferably 0.09 or more. By setting the refractive index difference at a wavelength of 630 nm within this range, an effect of suppressing in-plane color change during light guide is achieved.

[0041] The light-scattering region 15 is provided between the low-refractive-index intermediate layer 14 and the second glass plate 12. The light-scattering region 15 scatters light 31 incident from the light source toward the fourth main surface 24. A light-scattering pattern is formed in the light-scattering region 15, and the non-light-scattering region 16 is in direct contact with the low-refractive-index intermediate layer 14 and the third main surface 23 of the second glass plate 12. For example, the light-scattering region 15 may be provided by forming a light-scattering pattern on the third main surface 23 of the second glass plate 12. The light-scattering pattern can be formed by roughening the surface of the glass plate by physical or chemical etching, or by printing a scattering material containing inorganic or organic fine particles on the surface of the glass plate.

[0042] Light 31 introduced into the edge of laminated glass 1a from a light source (not shown), such as an LED, propagates in the in-plane direction of laminated glass 1a. In other words, in this embodiment, the difference in refractive index between light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14 is 0.05 or more, so that most components of light 31 are preferably totally reflected at the interface between light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14. Most components of light 31 are also preferably totally reflected at fourth main surface 24 of second glass plate 12. Thus, light 31 propagates through second glass plate 12 and low-refractive-index intermediate layer 14. At this time, part of light 31 is scattered by light-scattering region 15 and extracted from fourth main surface 24 of laminated glass 1a.

[0043] Furthermore, in this embodiment, the light source and light scattering region 15 are provided closer to the fourth main surface 24 than the light absorbing intermediate layer 13, so that light can be prevented from being absorbed and attenuated by the light absorbing intermediate layer 13.

[0044] In the laminated glass 1a according to this embodiment, the visible light reflectance measured from the fourth main surface 24 side is preferably 15% or less, more preferably 10% or less. The visible light reflectance measured from the fourth main surface 24 side is preferably 3% or more, more preferably 5% or more. The visible light reflectance represents a measurement value in a portion where a light-scattering pattern is not formed (i.e., non-light-scattering region 16). By setting the visible light reflectance measured from the fourth main surface 24 side within this range (i.e., reducing the visible light reflectance), the light scattered in the light-scattering region 15 can be more easily recognized by the user.

[0045] That is, when the light-absorbing intermediate layer 13 is provided, the laminated glass 1a becomes dark, causing reflection of light from inside the vehicle. This can make it difficult for the user to see the light extracted from the fourth main surface 24. In contrast, in the present embodiment, the visible light reflectance measured from the fourth main surface 24 side is low, making it easier for the user to see the light extracted from the fourth main surface 24.

[0046] Furthermore, in the laminated glass 1a according to this embodiment, the visible light transmittance measured from the fourth main surface 24 side in the region 16 other than the light scattering region 15 is preferably 30% or less, and more preferably 20%. By setting the visible light transmittance measured from the fourth main surface 24 side within this range (i.e., by reducing the visible light transmittance), it is possible to make it difficult for light to enter from outside. This makes it easier for the user to view the light extracted from the fourth main surface 24. Note that the region 16 other than the light scattering region 15 is a region where the light scattering region 15 (scattering layer) is not provided and where no light-scattering pattern is formed.

[0047] The visible light transmittance of the second glass plate 12 is preferably 85% or more, and more preferably 90%. By setting the visible light transmittance of the second glass plate 12 to this range, it is possible to suppress light from being absorbed and attenuated in the second glass plate 12. Furthermore, it is possible to suppress attenuation of light scattered in the light-scattering region 15 when it passes through the second glass plate 12, which makes it easier for the user to view the light extracted from the fourth main surface 24.

[0048] Second Embodiment Next, a structural example of a laminated glass according to a second embodiment will be described with reference to the cross-sectional view shown in Fig. 2. The laminated glass 1b according to the present embodiment shown in Fig. 2 differs from the laminated glass 1a according to the first embodiment shown in Fig. 1 in the position where the light scattering region 15 is provided and the position where light is introduced (i.e., the position of the light source). The rest of the structure is the same as that of the laminated glass 1a according to the first embodiment shown in Fig. 1, so the same components are denoted by the same reference numerals and redundant description will be omitted where appropriate.

[0049] As shown in FIG. 2 , in laminated glass 1b according to this embodiment, light-scattering region 15 is provided between light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14. Specifically, light-scattering region 15 is formed on the surface of light-absorbing intermediate layer 13 facing fourth principal surface 24 or on the surface of low-refractive-index intermediate layer 14 facing first principal surface 21. Light-scattering region 15 scatters light 31 incident from the light source toward fourth principal surface 24. Light-scattering region 15 has a light-scattering pattern formed therein, and in non-light-scattering region 16, light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14 are in direct contact with each other. For example, the light-scattering pattern may be a scattering material containing inorganic or organic fine particles.

[0050] In laminated glass 1b according to the present embodiment, light 31 is introduced into low-refractive-index intermediate layer 14. Light 31 introduced into low-refractive-index intermediate layer 14 propagates in the in-plane direction of laminated glass 1b. That is, in laminated glass 1b according to the present embodiment, the difference in refractive index between light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14 is also 0.05 or greater. Therefore, most of the components of light 31 are preferably totally reflected at the interface between light-absorbing intermediate layer 13 and low-refractive-index intermediate layer 14. Furthermore, the difference in refractive index between second glass plate 12 and low-refractive-index intermediate layer 14 is also 0.05 or greater. Therefore, most of the components of light 31 are preferably totally reflected at the interface between second glass plate 12 and low-refractive-index intermediate layer 14 (i.e., third principal surface 23). Therefore, light 31 propagates through low-refractive-index intermediate layer 14. At this time, a portion of light 31 is scattered by light-scattering region 15 and extracted from the fourth principal surface 24 of laminated glass 1b.

[0051] The laminated glass 1b according to this embodiment also provides the same effects as those of the laminated glass 1a according to the first embodiment.

[0052] In the laminated glass 1b shown in Fig. 2, light 31 may be introduced into the second glass plate 12 (see Fig. 1). In this case, the light 31 introduced into the second glass plate 12 propagates through the second glass plate 12 and the low-refractive-index intermediate layer 14. At this time, part of the light 31 is scattered in the light-scattering region 15 and extracted from the fourth main surface 24 of the laminated glass 1b.

[0053] <Third Embodiment> Next, a structural example of a laminated glass according to a third embodiment will be described using the cross-sectional view shown in Fig. 3. A laminated glass 1c according to the third embodiment shown in Fig. 3 differs from the laminated glass 1a according to the first embodiment shown in Fig. 1 in that it does not include a low-refractive-index intermediate layer 14. The rest of the structure is the same as that of the laminated glass 1a according to the first embodiment shown in Fig. 1, so the same components are denoted by the same reference numerals and redundant description will be omitted where appropriate.

[0054] As shown in Fig. 3 , in laminated glass 1c according to this embodiment, light-absorbing intermediate layer 13 is sandwiched between second main surface 22 of first glass plate 11 and third main surface 23 of second glass plate 12. In other words, first glass plate 11 and second glass plate 12 are bonded together using light-absorbing intermediate layer 13.

[0055] Light-scattering region 15 is provided between light-absorbing intermediate layer 13 and second glass plate 12. Light-scattering region 15 scatters light 31 incident from the light source toward fourth main surface 24. A pattern that scatters light is formed in light-scattering region 15, and non-light-scattering region 16 is in direct contact with light-absorbing intermediate layer 13 and third main surface 23 of second glass plate 12. For example, light-scattering region 15 may be provided by forming a pattern that scatters light on third main surface 23 of second glass plate 12.

[0056] In laminated glass 1c according to the present embodiment, the difference in refractive index between light-absorbing intermediate layer 13 and second glass plate 12 is preferably 0.05 or more, more preferably 0.07 or more, and even more preferably 0.09 or more. Furthermore, the difference in refractive index between light-absorbing intermediate layer 13 and second glass plate 12 is preferably 0.2 or less, more preferably 0.15 or less. By setting the difference in refractive index between light-absorbing intermediate layer 13 and second glass plate 12 within this range, the amount of light incident on light-absorbing intermediate layer 13 from second glass plate 12 can be reduced. Therefore, the amount of light absorbed by light-absorbing intermediate layer 13 can be reduced, allowing light to propagate farther within the laminated glass.

[0057] In laminated glass 1c according to the present embodiment, light 31 is introduced into second glass plate 12. In laminated glass 1c according to the present embodiment, the difference in refractive index between light-absorbing intermediate layer 13 and second glass plate 12 is 0.05 or more, and therefore light 31 is totally reflected at the interface between light-absorbing intermediate layer 13 and second glass plate 12. Light 31 is also totally reflected at fourth main surface 24 of second glass plate 12. Thus, light 31 propagates within second glass plate 12. At this time, part of light 31 is scattered in light-scattering region 15 and extracted from fourth main surface 24 of laminated glass 1c.

[0058] The laminated glass 1c according to this embodiment also provides the same effects as those of the laminated glass 1a according to the first embodiment.

[0059] Next, examples will be described. Laminated glasses according to Examples 1 to 13 were produced by the following method. Tables 1 and 2 show the configurations of the laminated glasses according to Examples 1 to 13.

[0060] Example 1 A laminated glass having the configuration shown in FIG. 1 was fabricated as the laminated glass of Example 1. Specifically, a 2.0 mm thick clear glass (manufactured by AGC: refractive index n = 1.52) was prepared as the first glass plate 11. A 0.76 mm thick gray interlayer (refractive index n = 1.48) was prepared as the light-absorbing interlayer 13. A 0.02 mm thick transparent clear interlayer (refractive index n = 1.45) was prepared as the low-refractive index interlayer 14. One main surface of the low-refractive index interlayer 14 was previously provided with a 0.02 mm thick scattering pattern containing light-scattering fine particles as the light-scattering region 15 (scattering layer). The scattering pattern had dot shapes with a diameter of approximately 5 mm scattered at a predetermined interval so as to occupy a total area of ​​30% or less of the total area of ​​the clear interlayer. A 2.1 mm thick high-transmittance glass (manufactured by AGC: refractive index n = 1.52) was prepared as the second glass plate 12. In this specification, unless otherwise specified, the refractive index is a refractive index measured at a wavelength of 589 nm under conditions of 25°C.

[0061] Then, a first glass plate 11, a light-absorbing intermediate layer 13, a low-refractive-index intermediate layer 14 with a light-scattering region 15 (scattering layer), and a second glass plate 12 were laminated in this order, and this laminate was placed in a vacuum bag and bonded at a temperature of approximately 70°C to 110°C in a vacuum with a gauge pressure of -65 kPa to -100 kPa. The bonded laminate was then heated and pressurized in an autoclave at a temperature of 100°C to 150°C and a pressure of 0.6 to 1.3 MPa to produce the laminated glass of Example 1. At this time, the light-scattering region 15 (scattering layer) was located at the interface between the low-refractive-index intermediate layer 14 and the second glass plate 12. In Example 1, a light source was provided at the edge of the second glass plate 12, and light 31 was introduced into the second glass plate 12.

[0062] Example 2 A laminated glass according to Example 2 was produced in which the light-scattering region 15 (scattering layer) of Example 1 was provided on the fourth main surface 24 of the second glass plate 12. The rest of the laminated glass was the same as that of Example 1. That is, the scattering pattern provided on the fourth main surface 24 of the second glass plate 12 was made of the same material and had the same design as the scattering pattern provided on one main surface of the low-refractive-index intermediate layer 14 in Example 1.

[0063] Example 3 A laminated glass having the configuration shown in Fig. 2 was produced as a laminated glass according to Example 3. Specifically, the same materials as those in Example 1 were prepared for the first glass plate 11, light-absorbing intermediate layer 13, light-scattering region 15 (scattering layer), low-refractive-index intermediate layer 14, and second glass plate 12.

[0064] Then, a first glass plate 11, a light-absorbing intermediate layer 13, a low-refractive-index intermediate layer 14 with a light-scattering region 15 (scattering layer), and a second glass plate 12 were laminated in this order, and this laminate was placed in a vacuum bag and bonded at a temperature of approximately 70°C to 110°C in a vacuum with a gauge pressure of -65 kPa to -100 kPa. The bonded laminate was then heated and pressurized in an autoclave at a temperature of 100°C to 150°C and a pressure of 0.6 to 1.3 MPa to produce a laminated glass according to Example 3. At this time, the light-scattering region 15 (scattering layer) was located at the interface between the light-absorbing intermediate layer 13 and the low-refractive-index intermediate layer 14. In Example 3, a light source was provided at the end of the low-refractive-index intermediate layer 14, and light 31 was introduced into the low-refractive-index intermediate layer 14.

[0065] Example 4 A laminated glass according to Example 4 was produced using a high-refractive-index, high-transmittance glass (manufactured by AGC: thickness 2.1 mm) with a refractive index n of 1.58 as the second glass plate 12. Other than this, the laminated glass was the same as that according to Example 1.

[0066] Example 5 As the laminated glass of Example 5, a sample was produced in which a light source was provided at the edge of the first glass plate 11 and light was introduced into the first glass plate 11. Other than this, the laminated glass of Example 1 was the same as that of Example 1.

[0067] Example 6 As the laminated glass of Example 6, a laminated glass was produced in which a transparent clear interlayer film (thickness: 0.76 mm) having a refractive index n = 1.50 was used as the low refractive index interlayer 14. Other than this, the laminated glass was the same as that of Example 1.

[0068] Example 7 As the laminated glass of Example 7, a laminated glass was produced in which a reflective coating was applied to the fourth main surface 24 of the laminated glass of Example 1. The reflective coating was a SiO ２ and TiO ２ Other than this, the laminated glass was the same as in Example 1.

[0069] Example 8 A laminated glass according to Example 8 was produced by using gray glass (manufactured by AGC: thickness 2.0 mm: refractive index n = 1.52) instead of the first glass plate 11 (clear glass) of Example 1, and a transparent clear interlayer film (thickness 0.76 mm: refractive index n = 1.48) instead of the light-absorbing interlayer 13 (gray interlayer film) of Example 1. Other than this, the laminated glass was the same as that of Example 1.

[0070] Example 9 As a laminated glass according to Example 9, a laminated glass was produced in which the light-scattering region 15 (scattering layer) of FIG. 3 was provided on the fourth main surface 24 of the second glass plate 12. Specifically, the same materials as those in Example 1 were prepared for the first glass plate 11, the light-absorbing intermediate layer 13, the second glass plate 12, and the light-scattering region 15 (scattering layer). In Example 9, the light-scattering region 15 (scattering layer) was provided on the fourth main surface 24 of the second glass plate 12. The scattering pattern in Example 9 was made of the same material and had the same design as the scattering pattern provided on one main surface of the low-refractive-index intermediate layer 14 in Example 1.

[0071] Then, the first glass plate 11, the light-absorbing intermediate layer 13, and the second glass plate 12 with the light-scattering region 15 (scattering layer) were laminated in this order, and this laminate was placed in a vacuum bag and bonded at a temperature of approximately 70°C to 110°C in a vacuum of a gauge pressure of -65 kPa to -100 kPa. The bonded laminate was then heated and pressurized in an autoclave at a temperature of 100°C to 150°C and a pressure of 0.6 to 1.3 MPa to produce the laminated glass of Example 9. In Example 9, a light source was provided at the edge of the second glass plate 12, and light 31 was introduced into the second glass plate 12.

[0072] Example 10 A laminated glass according to Example 10 was produced in which the light-scattering region 15 (scattering layer) of Example 9 was provided on the third main surface 23 of the second glass plate 12. The rest of the laminated glass was the same as that of Example 9. That is, the scattering pattern provided on the third main surface 23 of the second glass plate 12 was made of the same material and had the same design as the scattering pattern provided on the fourth main surface 24 of the second glass plate 12 in Example 9.

[0073] Example 11 As a laminated glass according to Example 11, a laminated glass was produced in which a clear interlayer film (thickness: 0.76 mm) having a refractive index n=1.47 at a wavelength of 630 nm was used as the low-refractive-index interlayer 14. Other than this, the laminated glass was the same as that according to Example 1.

[0074] Example 12 A laminated glass according to Example 12 was produced using a clear interlayer film (thickness: 0.76 mm) with a refractive index n = 1.43 at a wavelength of 630 nm as the low-refractive-index interlayer 14. Other than this, the laminated glass was the same as that according to Example 1.

[0075] Example 13 As a laminated glass according to Example 13, a laminated glass was produced in which a clear interlayer film (thickness: 0.76 mm) having a refractive index n=1.49 at a wavelength of 630 nm was used as the low-refractive-index interlayer 14. Other than this, the laminated glass was the same as that according to Example 1.

[0076] <Evaluation of Samples> The visible light transmittance, visible light reflectance, refractive index difference (three-point average), refractive index difference at 630 nm, and transmittance of the second glass plate (2 mm calculation) of each laminated glass prepared as described above were determined.

[0077] The visible light transmittance is the visible light transmittance measured from the fourth main surface 24 side in the region 16 other than the light scattering region 15 (scattering layer). A spectrometer (UH4150, manufactured by Hitachi Corporation) was used to measure the visible light transmittance. The visible light reflectance is the visible light reflectance measured from the fourth main surface 24 side. A spectrometer (UH4150, manufactured by Hitachi Corporation) was used to measure the visible light reflectance.

[0078] The refractive index difference (three-point average) was determined by calculating the average value of the refractive indices at wavelengths of 656 nm, 589 nm, and 486 nm. The refractive index difference at 630 nm was determined from the difference between the refractive index of the second glass plate and the refractive index of the adjacent interlayer film. The transmittance of the second glass plate (2 mm calculation) was determined using a spectrometer.

[0079] Furthermore, the following evaluation was carried out for evaluation item 1. A 1 (lm) LED was used as a light source, and the luminance was 0.5 (cd / m) at a point 100 mm away from the light source in the in-plane direction of the laminated glass. ２ ) or more and the contrast was more than 1.2, the result was rated as "OK." If the scattering pattern was not clearly visible, the result was rated as "NG."

[0080] Additionally, for evaluation item 2, the following evaluations 1 to 4 were carried out. Evaluation item 2 is an item for evaluating the effect when the refractive index difference at a wavelength of 630 nm is set to 0.05 or more. 1: Even when white light was used as the light source, light reached the entire surface evenly. 2: When any color of RGB was used as the light source, light reached the entire surface. 3: When red light was used as the light source, the entire surface was dark. 4: No light reached the entire surface regardless of the color of the light source used.

[0081] The evaluation results of the laminated glasses of Examples 1 to 13 are shown in Tables 1 and 2. In Tables 1 and 2, the notation "+light source" indicates the position of the light source. For example, the notation "high transmittance glass + light source" in the column for the second glass in Example 1 indicates that a high transmittance glass was used as the second glass, and the light source was positioned so that light was incident on the high transmittance glass.

[0082]

[0083]

[0084] <Summary of Results> The laminated glasses of Examples 1 to 4 and Examples 9 to 13 are laminated glasses according to Examples, and the laminated glasses of Examples 5 to 8 are laminated glasses according to Comparative Examples. The evaluation results of the laminated glasses of Examples 1 to 13 will be described in detail below.

[0085] In the laminated glass of Examples 1 to 4, the difference in refractive index between the light-absorbing intermediate layer 13 (gray interlayer) and the low-refractive-index intermediate layer 14 (clear interlayer) was 0.05 or more. Furthermore, the visible light transmittance measured from the fourth principal surface 24 side was 30% or less, and the visible light reflectance measured from the fourth principal surface 24 side was 15% or less. Therefore, light was transmitted well through the laminated glass, and the reflection of light from inside the vehicle cabin onto the laminated glass was suppressed. Furthermore, the influence of transmitted light from outside the vehicle was suppressed. Therefore, the light extracted from the fourth principal surface 24 was easily visible to the user, and evaluation item 1 was evaluated as "OK."

[0086] In the laminated glass of Example 5, a light source was provided at the edge of the first glass plate 11, and light was introduced into the first glass plate 11. As a result, light did not propagate well inside the laminated glass, and evaluation item 1 was evaluated as "NG." In the laminated glass of Example 6, the refractive index difference between the light-absorbing intermediate layer 13 (gray interlayer) and the low refractive index intermediate layer 14 (clear interlayer) was 0.02. As a result, light did not propagate well inside the laminated glass, and evaluation item 1 was evaluated as "NG."

[0087] In the laminated glass of Example 7, although the difference in refractive index between the light-absorbing intermediate layer 13 (gray intermediate film) and the low-refractive-index intermediate layer 14 (clear intermediate film) was 0.05 or more, light from inside the vehicle cabin was reflected on the laminated glass, reducing the visibility of the scattering pattern. Therefore, evaluation item 1 was rated "NG." Furthermore, because a reflective coating was applied to the fourth main surface 24, the visible light reflectance was a high value of 20%.

[0088] In the laminated glass of Example 8, the difference in refractive index between the gray glass and the clear interlayer film was 0.05 or more, but the visible light transmittance was as high as 39%, and the visibility of the scattering pattern was reduced due to the influence of transmitted light from outside the vehicle. For this reason, evaluation item 1 was given a rating of "NG."

[0089] In the laminated glass of Examples 9 and 10, the difference in refractive index between the light-absorbing intermediate layer 13 (gray interlayer) and the second glass plate 12 (high-transmittance glass) was 0.05 or more. Furthermore, the visible light transmittance measured from the fourth main surface 24 side was 30% or less, and the visible light reflectance measured from the fourth main surface 24 side was 15% or less. Therefore, light was transmitted well through the laminated glass, and the reflection of light from inside the vehicle cabin onto the laminated glass was suppressed. Furthermore, the influence of transmitted light from outside the vehicle was suppressed. Therefore, the light extracted from the fourth main surface 24 was easily visible to the user, and evaluation item 1 was evaluated as "OK."

[0090] In the laminated glass of Examples 11 to 13, the difference in refractive index between the light-absorbing intermediate layer 13 (gray interlayer) and the low-refractive-index intermediate layer 14 (clear interlayer) was 0.05 or more. Furthermore, the visible light transmittance measured from the fourth principal surface 24 side was 30% or less, and the visible light reflectance measured from the fourth principal surface 24 side was 15% or less. Therefore, light was transmitted well through the laminated glass, and the reflection of light from inside the vehicle cabin onto the laminated glass was suppressed. Furthermore, the influence of transmitted light from outside the vehicle was suppressed. Therefore, the light extracted from the fourth principal surface 24 was easily visible to the user, and evaluation item 1 was evaluated as "OK."

[0091] Focusing on the refractive index difference at a wavelength of 630 nm, the refractive index difference was 0.05 in Example 11 and 0.09 in Example 12. Therefore, the evaluation of evaluation item 2 was good, with Example 11 receiving a rating of "2" and Example 12 receiving a rating of "1." On the other hand, in Example 13, the refractive index difference at a wavelength of 630 nm was low at 0.03, and therefore the evaluation of evaluation item 2 was "3."

[0092] The present invention has been described above in accordance with the above-mentioned embodiment, but the present invention is not limited to the configuration of the above-mentioned embodiment, and naturally includes various modifications, alterations, and combinations that a person skilled in the art can make within the scope of the invention as defined in the claims of this application.

[0093] This application claims priority based on Japanese Patent Application No. 2023-171722, filed October 3, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0094] 1a, 1b, 1c Laminated glass 11 First glass plate 12 Second glass plate 13 Light-absorbing intermediate layer 14 Low-refractive-index intermediate layer 15 Light-scattering region 16 Region other than light-scattering region 21 First main surface 22 Second main surface 23 Third main surface 24 Fourth main surface 31 Light

Claims

1. A laminated glass comprising: a first glass plate having a first principal surface and a second principal surface; a second glass plate having a third principal surface and a fourth principal surface; a light absorbing intermediate layer disposed between said first glass plate and said second glass plate; and a light scattering region disposed on said fourth principal surface side of said light absorbing intermediate layer, wherein said second principal surface and said third principal surface face each other, said light scattering region scatters light incident from a light source towards said fourth principal surface side, a refractive index difference between said light absorbing intermediate layer and a member contacting said light absorbing intermediate layer on the fourth principal surface side is 0.05 or more, a visible light reflectance measured from the fourth principal surface side is 15% or less, and a visible light transmittance measured from the fourth principal surface side in a region other than said light scattering region is 30% or less.

2. The laminated glass according to claim 1, wherein the member in contact with the light absorbing intermediate layer on the fourth main surface side is a low refractive index intermediate layer.

3. The laminated glass according to claim 1, wherein the member in contact with the light absorbing intermediate layer on the fourth main surface side is the second glass plate.

4. The laminated glass according to claim 2, wherein the low refractive index intermediate layer contains at least one selected from the group consisting of polyvinyl butyral resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, ionomer resin, and cycloolefin polymer, or an acrylic-, silicone-, epoxy-, or urethane acrylate-based optical adhesive material.

5. The laminated glass according to claim 1 or 2, wherein the light-absorbing intermediate layer contains at least one material selected from the group consisting of polyvinyl butyral resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, ionomer resin, and cycloolefin polymer.

6. The laminated glass according to claim 1 or 2, wherein the light absorbing intermediate layer has a visible light transmittance of 30% or less.

7. The laminated glass according to claim 1 or 2, wherein the light-absorbing intermediate layer is made of a resin material containing a pigment.

8. The laminated glass according to claim 1 or 2, wherein the refractive index difference at a wavelength of 630 nm is 0.05 or more.

9. The laminated glass according to claim 1 or 2, wherein the second glass sheet has a visible light transmittance of 85% or more.

10. The laminated glass according to claim 1 or 2, wherein the light scattering region is formed on the third main surface of the second glass plate or on the surface of the light absorbing intermediate layer facing the fourth main surface.

11. The laminated glass according to claim 1 or 2, wherein the refractive index difference is 0.2 or less.

12. The laminated glass according to claim 1 or 2, which has a visible light reflectance measured from the fourth main surface side of 3% or more.

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