Automobile window glass

Abstract

An automobile window glass according to the present invention comprises: an outside glass sheet; an inside glass sheet; and an intermediate film that bonds the outside glass sheet and the inside glass sheet and substantially does not have infrared absorption performance, wherein the heat feeling transmittance (Ttf) is 44.0% or less.

Description

Automobile window glass

[0001] The present invention relates to automobile window glass.

[0002] Automobile window glass provided on a windshield, side door, rearview mirror, roof, etc. is generally required to cut ultraviolet rays contained in sunlight incident from outside the vehicle. As a method, for example, it has been proposed to dispose an ultraviolet absorber in the interlayer film of laminated glass (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-64965

[0004] However, the ultraviolet ray absorption ability is a function already provided in the interlayer film. When it is provided in both the interlayer film and the inner and outer glass plates, it becomes excessive quality. On the other hand, in order to reduce the heat felt by a person riding in a passenger car, there is an example of adding an infrared absorber to the interlayer film. In this case, there is a problem that the price of the interlayer film increases and the production cost rises.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide an automobile window glass capable of improving infrared absorption performance without depending on an interlayer film.

[0006] Item 1. An automobile window glass comprising: an outer glass plate; an inner glass plate; and an interlayer film that adheres the outer glass plate and the inner glass plate and substantially has no infrared absorption performance, and having a heat and summer feeling transmittance (Ttf) of 44.0% or less.

[0007] Item 2. The automobile window glass according to Item 1, wherein the chromaticity b* in the CIE standard is 2.0 or less.

[0008] Item 3. The automobile window glass according to Item 1, wherein the chromaticity b* in the CIE standard is 1.5 or less.

[0009] Item 4. The automobile window glass according to any one of Items 1 to 3, wherein the visible light transmittance YA measured based on JIS R3106:1998 using the A light source in the CIE standard is 72.0% or more.

[0010] Item 5. An automobile window glass according to any one of items 1 to 4, wherein at least one of the outer glass plate and the inner glass plate contains t-Fe2O3, which is the total iron oxide content converted to Fe2O3, at a rate of 0.60% by mass or more, and the sum of CeO2 and TiO2 is 0.10% by mass or less, and the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3 converted to Fe2O3, is 25% or more.

[0011] Item 6. The automotive window glass according to any one of items 1 to 4, wherein both the outer glass plate and the inner glass plate contain t-Fe2O3, which is the total iron oxide content converted to Fe2O3, at a rate of 0.60% by mass or more, and the sum of CeO2 and TiO2 is 0.05% by mass or less, and the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3 converted to Fe2O3, is 25% or more.

[0012] Item 7. Automotive window glass according to any one of items 1 to 6, wherein at least one of the outer glass plate and the inner glass plate has a visible light transmittance YA of 81.5% or more and 83.5% or less, and a Tuv (ISO 9050-2003) of 0.5 or more relative to the thermal transmittance.

[0013] Item 8. Automotive window glass according to any one of items 1 to 6, wherein both the outer glass plate and the inner glass plate have a visible light transmittance YA of 81.5% or more and 83.5% or less, and a Tuv (ISO 9050-2003) of 0.5 or more relative to the thermal transmittance.

[0014] Item 9. A windshield using the automotive window glass described in any of items 1 to 8.

[0015] Item 10. The windshield described in item 9, which extends above the driver's seat.

[0016] According to the present invention, infrared absorption performance can be improved without the use of an interlayer.

[0017] This is a plan view showing one embodiment in which the automotive window glass according to the present invention is applied to a windshield. This is a cross-sectional view of Figure 1. This is a block diagram showing the schematic configuration of an in-vehicle system.

[0018] Hereinafter, an embodiment of the application of the automotive window glass according to the present invention to a windshield will be described with reference to the drawings. Figure 1 is a plan view of the windshield, and Figure 2 is a cross-sectional view of Figure 1. For the sake of convenience in the explanation, the vertical direction in Figure 1 will be referred to as "up and down," "vertical," or "vertical," and the left and right direction in Figure 1 will be referred to as "left and right." Figure 1 illustrates the windshield as seen from the inside of the vehicle. That is, the far side of Figure 1 is the outside of the vehicle, and the near side of Figure 1 is the inside of the vehicle.

[0019] This windshield is equipped with a trapezoidal laminated glass 10 and is installed on the vehicle body in an inclined position. The laminated glass 10 has an outer glass plate 11, an inner glass plate 12, and an interlayer 13 placed between them. A shielding layer 4 is laminated on the in-vehicle side surface of the inner glass plate 12, and this shielding layer 4 blocks the view from outside the vehicle. An opening 43 is formed in this shielding layer 4, and through this opening 43, the outside situation can be photographed by a camera 2 placed inside the vehicle. In other words, this opening 43 constitutes a camera window. Furthermore, a frame-shaped bracket 6 is fixed on the shielding layer 4 of the inner glass plate 12, and the camera 2 is attached to this bracket 6. Since the bracket 6 is formed in a frame shape and fixed on the shielding layer 4, the bracket 6 is not visible from outside the vehicle. The following describes each component in detail.

[0020] <1. Laminated Glass> Figure 2 is a cross-sectional view of laminated glass. As shown in the figure, this laminated glass 10 comprises an outer glass plate 11 and an inner glass plate 12, with a resin interlayer 13 placed between these glass plates 11 and 12. The following describes these components.

[0021] <1-1. Glass Plates> First, the outer glass plate 11 and the inner glass plate 12 will be explained. The outer glass plate 11 and the inner glass plate 12 can be made of, for example, heat-absorbing glass, clear glass, green glass, or UV green glass. Below, the physical properties required for the glass plate will be explained first, and then the composition of the glass plate will be explained.

[0022] <1-1-1. Physical Properties of the Glass Plate> The physical properties of the glass plate in this embodiment will be described below.

[0023] (1) In order to describe the relationship between the optical properties of heat sensation transmittance and heat sensation, the heat sensation transmittance was defined as follows.

[0024] (Relationship between skin temperature increase and heat sensation) First, the relationship between the increase in a person's skin temperature due to incident sunlight and the heat sensation felt by the person's skin was evaluated. The procedure was as follows: A filter was attached to the light beam emitted from a xenon lamp (Seric XC-500E) to obtain a light source with an energy distribution equivalent to that of sunlight. A panel with a 50 mm diameter hole was placed 416 mm from the light source. The back of the subject's hand was placed on the opposite side of the light source through the hole, and the temperature of the subject's hand was measured every 3 seconds using a thermal viewer. The subject reported their heat sensation on a 5-point scale: (1) slightly warm, (2) warm, (3) slightly hot, (4) hot, and (5) very hot. The heat sensation felt by people was compiled from the results of an experiment conducted on 81 subjects. As a result, there was a proportional relationship between skin temperature increase and heat sensation, with a 0.5°C increase in skin temperature causing an increase in heat sensation of approximately one level. Furthermore, it was confirmed that when the increase in skin temperature is 3.2°C or less, people do not perceive it as "very hot."

[0025] (Skin Sensitivity) The degree of increase in skin temperature depends on the wavelength of sunlight. The degree of increase in skin temperature, which depends on the wavelength, can be quantified as a coefficient at that wavelength (skin sensitivity; sensitivity ratio for thermal feeling; hereinafter sometimes referred to as "SRTF"). The SRTFs for the wavelength ranges of 300-840 nm and 840-1350 nm have been reported to be 1.43 and 1, respectively, with the value at 840-1350 nm set to 1. However, the SRTF for the wavelength range of 1350-2500 nm had not been clarified, despite its significant impact on the feeling of heat. Therefore, the SRTF in this wavelength range was determined by experiments using light in the wavelength range of 1350-2500 nm, obtained by replacing the filter and extracting it from the aforementioned light source. This experiment was also conducted by measuring the temperature increase on the back of the subject's hand. The SRTF in the wavelength range of 1350-2500 nm was found to be 3.34. For wavelengths below 300 nm and above 2500 nm, the SRTF can be considered virtually zero. Table 1 summarizes the skin sensitivity in each wavelength range.

[0026]

[0027] (Transmittance for thermal feeling) By weighting the product of the spectral transmittance of the glass plate and the spectrum of sunlight using the skin sensitivity shown in Table 1, the thermal feeling actually perceived by a person can be described more accurately using the optical properties of the glass plate. Here, "transmittance for thermal feeling (Ttf)" is defined by the following formula.

[0028]

[0029] Here, Isun(λ) is the spectrum of sunlight in Air mass 1.5 as defined in ISO 9845-1, Tglass(λ) is the spectral transmittance of the glass plate, and SR(λ) is the skin sensitivity shown in Table 1. Tair(λ) is the spectral transmittance of the atmosphere, which is set to 1 regardless of wavelength.

[0030] The relationship between the increase in skin temperature due to sunlight transmitted through a glass plate and the heat sensation transmittance defined by the above formula was evaluated and confirmed as follows. In the evaluation apparatus described above, a glass plate or laminated glass was placed approximately midway between the light source and the back of the subject's hand, such that the normal to the glass surface and the line connecting the light source and the back of the subject's hand formed a 30-degree angle, and the increase in skin temperature was measured. The increase in skin temperature was calculated by summarizing the results of experiments conducted on 111 subjects. As a result, a good correlation was confirmed between the increase in skin temperature and the heat sensation transmittance.

[0031] Furthermore, the results of the above research showed that in order to prevent people from feeling excessively hot, window glass that causes a rise in skin temperature of 3.5°C or less should be used. In other words, the thermal transmittance (Ttf) of the glass plate or laminated glass used as window glass should be set to approximately 44% or less, preferably 43% or less, more preferably 42% or less, and even more preferably 40% or less.

[0032] A higher FeO content results in higher infrared absorption performance. As a result, Ttf can be reduced. From this viewpoint, the FeO content is preferably, for example, 0.2% by mass or more. In addition, although not as high as FeO, a high Fe2O3 content can also reduce Ttf. For example, if the total iron oxide content converted to Fe2O3 is taken as t-Fe2O3, the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3, is preferably 25% to 30%, and more preferably 28% to 30%. This increases infrared absorption performance and lowers Ttf.

[0033] (2) UV transmittance As described later, the interlayer 13 formed of resin material may deteriorate due to ultraviolet rays incident from outside the vehicle, so the outer glass plate 11 of this embodiment has UV absorption properties. For this reason, for example, the Tuv (ISO 9050-2003) of the outer glass plate 11 is preferably 40.0% or less, and more preferably 30.0% or less.

[0034] To reduce Tuv, it is preferable to have a higher Fe2O3 content in the outer glass plate 11. The Fe2O3 content is preferably 0.5% by mass or more, and more preferably 0.6% by mass or more. However, since a high Fe2O3 content results in low visible light transmittance, it is preferable to have a Fe2O3 content of 0.7% by mass or less.

[0035] Furthermore, the glass plates 11 and 12 may contain TiO2 and CeO2, and a higher content of these can reduce Tuv. The total content of TiO2 and CeO2 is preferably, for example, 0.05% by mass or more, more preferably 0.10% by mass or more, and particularly preferably 0.20% by mass or more.

[0036] (3) CIE standard chromaticity b* Also, a higher Fe2O3 content results in a higher CIE standard chromaticity b*. For example, a higher chromaticity b* makes the glass plate appear yellowish, while a lower chromaticity b* makes the glass plate appear bluish. Since bluish colors are generally preferred for automotive windows, from this perspective, a low chromaticity b* is desirable, and for that purpose, a low Fe2O3 content is desirable. Such color adjustments can also be made by adjusting the TiO2 and CeO2 content. For example, a lower TiO2 and CeO2 content can lower the chromaticity b*.

[0037] Furthermore, if the FeO content in the glass plates 11 and 12 is high, the infrared absorption performance will increase, and the chromaticity b* will decrease. Therefore, in order to lower the chromaticity b*, for example, if the total iron oxide content converted to Fe2O3 is taken as t-Fe2O3, the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3, is preferably 25% or more and 30%, and more preferably 28% or more and 30%.

[0038] (4) Visible light transmittance YA: The visible light transmittance YA, measured using a CIE standard A light source in accordance with JIS R3106:1998, is preferably 81.5% or more and 83.5% or less.

[0039] When the visible light transmittance YA is less than 81.5%, the content of Fe₂O₃ may be too high. In that case, when laminated glass is formed using two glass plates with a visible light transmittance YA less than 81.5%, the visible light transmittance YA may be less than 70%, and it cannot be used as a windshield. However, because the content of Fe₂O₃ is high, the overall t-Fe₂O₃ becomes high, so Ttf becomes low. In this case, it becomes difficult to reduce Ttf while having a visible light transmittance YA sufficient for use in a windshield, but it can be used as a window glass such as a roof window where there is no problem even if YA is low.

[0040] As an example of a large content of coloring components other than t-Fe₂O₃, CoO or NiO can be contained. However, although these can lower the visible light transmittance YA, they have a poor function of lowering Ttf.

[0041] When the visible light transmittance YA is higher than 83.5%, the content of Fe₂O₃ may be too low. Therefore, there is a possibility that it does not contain sufficient t-Fe₂O₃ to reduce Ttf.

[0042] (5) Tuv / Ttf As described above, the preferable range of the visible light transmittance YA is not wide. That is, the preferable content range of t-Fe₂O₃ is also not wide. Therefore, Tuv / Ttf is considered. Tuv / Ttf is the "ease of ultraviolet transmission" with respect to the "ease of infrared transmission". In other words, it is the "infrared absorption ability" with respect to the "ultraviolet absorption performance". Therefore, the higher this value, the more FeO can be made in the limited t-Fe₂O₃, so Ttf can be reduced.

[0043] For example, if the visible light transmittance YA is 81.5% or more and 83.5% or less, and Tuv / Ttf satisfies 0.5 or more, Ttf becomes low, so it can be suitably used for a windshield.

[0044] Incidentally, TiO2, which is a coloring component that absorbs ultraviolet rays, greatly reduces Tuv, but at the same time reduces Ya as well (for example, the glass plate of Example 2 below, the glass plate 2 of the embodiment). On the other hand, TiO2 has little effect on lowering Ttf. Therefore, when TiO2 is added (although it may be contained unintentionally as a trace component of the raw material), Tuv / Ttf becomes higher. In this case, it becomes difficult to reduce Ttf while having a visible light transmittance YA sufficient for use in a windshield. Therefore, the upper limit of Tuv / Ttf is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 0.9 or less.

[0045] When forming the laminated glass, it is preferable to use one or more, preferably two, glass plates with Tuv / Ttf of 0.5 or more as described above.

[0046] Each of the glass plates 11 and 12 can have, for example, the following compositions.

[0047] (Example 1) - Fe2O3: 0.45% by mass or more and 0.60% by mass or less (preferably 0.50% by mass or more and 0.55% by mass or less), - FeO: 0.15% by mass or more and 0.30% by mass or less (preferably 0.20% by mass or more and 0.30% by mass or less), - CeO2: 0.05% by mass or less (including the case of 0% by mass, i.e., not contained), - TiO2: 0.05% by mass or less (including the case of 0% by mass, i.e., not contained), contained as a base composition, - The FeO ratio, which is the mass ratio of FeO to the t-Fe2O3 in terms of Fe2O3, is 20% or more and 30% or less (preferably 26% or more and 30% or less), - The total content of CeO2 and TiO2 is 0.1% by mass or less (preferably 0.05% by mass or less)

[0048] In Example 1, since the content of FeO is high, the infrared absorption performance is high. However, since the total content of CeO2 and TiO2 is low, the ultraviolet absorption performance is not higher than that of Example 2. However, this results in a low chromaticity b*.

[0049] (Example 2) The base composition contains: ・Fe2O3: 0.45% by mass or more and 0.60% by mass or less (preferably 0.55% by mass or more and 0.60% by mass or less), ・FeO: 0.15% by mass or more and 0.30% by mass or less (preferably 0.2% by mass or more and 0.3% by mass or less), ・CeO2: 0.05% by mass or more and 0.20% by mass or less (preferably 0.07% by mass or more), ・TiO2: 0.05% by mass or more and 1.0% by mass or less (preferably 0.10% by mass or 0.80% by mass or less), and ・The FeO ratio, expressed as the mass ratio of FeO to t-Fe2O3 converted to Fe2O3, is 20% or more and 30% or less (preferably 23% or more and 26% or less). - The total content of CeO2 and TiO2 is 0.1% by mass or more and 1.0% by mass or less (preferably 0.15% by mass or more, more preferably 0.20% by mass or more).

[0050] Example 2 has a high infrared absorption performance due to its high FeO content. Furthermore, its ultraviolet absorption performance is higher than Example 1 because of its high combined CeO2 and TiO2 content. However, this results in a slightly higher chromaticity b*.

[0051] For example, by combining glass plates like those in Example 1 and Example 2 described above, laminated glass with various properties can be formed. For instance, if laminated glass is constructed using at least one of Example 1 and Example 2, the infrared absorption performance is improved.

[0052] The thickness of the laminated glass 10 according to this embodiment is not particularly limited, but the sum of the thicknesses of the outer glass plate 11 and the inner glass plate 12 can be, for example, 2.1 to 6 mm. From the viewpoint of weight reduction, it is preferable that the sum of the thicknesses of the outer glass plate 11 and the inner glass plate 12 be 2.4 to 5.0 mm, more preferably 2.6 to 4.0 mm, and particularly preferably 2.7 to 3.2 mm. Thus, in order to reduce weight, it is necessary to reduce the sum of the thicknesses of the outer glass plate 11 and the inner glass plate 12, so the thickness of each glass plate is not particularly limited, but for example, the thicknesses of the outer glass plate 11 and the inner glass plate 12 can be determined as follows.

[0053] The outer glass plate 11 primarily needs to be durable and impact-resistant against external damage, and as a car windshield, it needs to be impact-resistant against flying objects such as pebbles. On the other hand, a greater thickness increases the weight, which is undesirable. From this viewpoint, the thickness of the outer glass plate 11 is preferably 1.8 to 2.3 mm, and more preferably 1.9 to 2.1 mm. The choice of thickness can be determined according to the application of the glass.

[0054] The thickness of the inner glass plate 12 can be the same as that of the outer glass plate 11, but for example, to reduce the weight of the laminated glass 10, its thickness can be made smaller than that of the outer glass plate 11. Specifically, considering the strength of the glass, a thickness of 0.6 to 2.0 mm is preferable, 0.8 to 1.6 mm is preferable, and 1.0 to 1.4 mm is particularly preferable. Furthermore, 0.8 to 1.3 mm is preferable. The thickness of the inner glass plate 12 can also be determined according to the application of the glass.

[0055] Here, we will describe an example of a method for measuring the thickness of a curved glass plate (laminated glass) 1. First, the measurement positions are two locations, one above and one below, on the center line S that extends vertically from the center of the glass plate in the left-right direction. The measuring instrument is not particularly limited, but for example, a thickness gauge such as the SM-112 manufactured by Teclock Co., Ltd. can be used. When measuring, the curved surface of the glass plate is placed on a flat surface, and the edge of the glass plate is clamped with the thickness gauge and measured. Note that even if the glass plate is flat, it can be measured in the same way as when it is curved.

[0056] <1-2. Interlayer> As shown in Figure 2, the interlayer 13 comprises a transparent first adhesive layer 131 that is bonded to the outer glass plate 11, a transparent second adhesive layer 132 that is bonded to the inner glass plate 12, and a transparent functional layer 133 that is placed between these two adhesive layers 131 and 132.

[0057] The first adhesive layer 131 and the second adhesive layer 132 can be made of materials that do not affect the light (visible light) incident on the camera when taking images with the imaging device 2, and that allow light to pass through. In other words, as will be described later, the materials of the two adhesive layers 131 and 132 are selected so that the image captured by the camera, which is formed by the light passing through both adhesive layers 131 and 132, is hardly affected by distortion or other influences from the two adhesive layers 131 and 132. The two adhesive layers 131 and 132 are bonded to each glass plate 11 and 12 by fusion, and can be formed from, for example, polyvinyl butyral resin (PVB) or ethylene vinyl acetate resin (EVA). In general, the hardness of polyvinyl acetal resin can be controlled by (a) the degree of polymerization of the starting material, polyvinyl alcohol, (b) the degree of acetalization, (c) the type of plasticizer, and (d) the proportion of plasticizer added.

[0058] As described above, the glass plates 11 and 12 possess infrared absorption performance (infrared cutting performance), so the interlayer 13 of this embodiment does not substantially possess infrared absorption performance. For example, if oxide fine particles (infrared absorbers) are included in the adhesive layers 131 and 132 or the functional layer 133, infrared absorption performance will be actively exhibited. Examples of oxide fine particles include tin-doped indium oxide (ITO), antimond-doped tin oxide (ATO), and aluminum-doped zinc oxide (AZO). However, even without using such oxide fine particles, the interlayer 13 may absorb a small amount of infrared radiation to an extent that is not practical. Therefore, saying that the interlayer 13 does not substantially possess infrared absorption performance means excluding the case where the interlayer 13 actively possesses a function to exhibit practical infrared absorption performance, such as by including oxide fine particles, while allowing the case where a small amount of infrared radiation is absorbed to an extent that is not practical.

[0059] The adhesive layers 131 and 132 of this embodiment can have ultraviolet absorption properties instead of infrared absorption properties. For example, at least one of the adhesive layers 131 and 132 can contain an ultraviolet absorber for absorbing ultraviolet rays. In particular, since the light-adjusting film described later is prone to degradation by ultraviolet rays, it is preferable to include an ultraviolet absorber. It is preferable that such an ultraviolet absorber be contained in the first adhesive layer 131. Furthermore, since such ultraviolet absorbers are prone to degradation by ultraviolet rays, it is preferable that the outer glass plate 11 has high ultraviolet absorption properties when using them.

[0060] Examples of UV absorbers that can be used include compounds having a malonic acid ester skeleton, compounds having an oxalic acid anilide skeleton, compounds having a benzotriazole skeleton, compounds having a benzophenone skeleton, compounds having a triazine skeleton, compounds having a benzoate skeleton, and compounds having a hindered amine skeleton. Among these, compounds having a benzotriazole skeleton (benzotriazole compounds) are preferred.

[0061] Specific examples of UV absorbers used in interlayers include the following: Benzotriazole type (1): Tinuvin 326, a compound represented by the following formula (1), where X is a chlorine atom, R21 is a methyl group, R22 is a tert-butyl group, Y1 is a hydrogen atom, and Y2 is a hydroxyl group. Trade name "Tinuvin 326", manufactured by Ciba Specialty Chemicals. Benzotriazole type (2): 2-(2,4-dihydroxyphenyl)-2H-benzotriazole

[0062] Before bonding to each glass plate 11, 12, the first adhesive layer 131 and the second adhesive layer 132 may be embossed on their surfaces to facilitate the expulsion of air when bonding to the functional layer 133 or to each glass plate 11, 12.

[0063] The thickness of the first adhesive layer 131 and the second adhesive layer 132 is not particularly limited, but is preferably 20 μm to 2.0 mm, more preferably 20 μm to 1.0 mm, and particularly preferably 50 to 100 μm. However, the thicknesses of both adhesive layers 131 and 132 may be the same or different. Furthermore, if an emboss is formed on each adhesive layer 131 and 132, it is preferable to set the thickness to 20 μm or more, taking into account the depth of the emboss, as described above. Alternatively, instead of using a sheet-like adhesive layer, the adhesive layers 131 and 132 can be formed by coating. In this case, a thin adhesive layer of 0.3 to 100 μm can be formed.

[0064] Furthermore, it is preferable that the combined thickness of both adhesive layers 131 and 132 be 0.76 mm or more. This is to ensure, for example, penetration resistance and other performance specified in JIS R3211 and R3212 for the windshield.

[0065] As the functional layer 133, various films with different functions can be used depending on the application. For example, known heat-shielding films, heat-generating films, projection films, light-emitting films, antenna films, and dimming films can be used.

[0066] The heating film is used to remove condensation or de-icing, and can consist of multiple fine wires that generate heat when a voltage is applied, supported by a base film. The base film can be any film that is transparent to visible light, and its material is not particularly limited, but it can be made of, for example, polyethylene terephthalate, polyethylene, polymethyl methacrylate, polyvinyl chloride, polyester, polyolefin, polycarbonate, polystyrene, polypropylene, nylon, etc. In addition to generating heat with fine wires, a transparent conductive film heater composed of, for example, a thin-film silver heater or an ITO heater can also be used.

[0067] The projection film is onto which information is projected by light emitted from a head-up display device (hereinafter referred to as HUD). The projection film is not particularly limited as long as it is a film that reflects light and has a different refractive index from the two adhesive layers 131 and 132, for example, a film whose polarization can be controlled, such as a p-polarizing reflective film, a hologram film, a transparent screen with a scattering reflective system, a transparent screen with a scattering transmission system, a dimmable film with a scattering reflective system, a dimmable film with a scattering transmission system, or a dimmable film for HUDs. The size of the projection film is not particularly limited, but it is preferably larger than the area on which the information is projected. The projection film may also be supported by a base film. The base film can be the same as the one used for the heat-generating film described above. The projection film may also be the same size as the base film, or it may be smaller than the base film. In this case, it is preferable that the outer edge of the projection film is located inward from the outer edge of the base film.

[0068] Furthermore, the base film can be placed on either the outer glass plate 11 side or the inner glass plate 12 side of the projection film. Alternatively, the projection film can be sandwiched between two base films.

[0069] The light-emitting film has built-in LEDs or similar elements that emit light to display predetermined characters, shapes, or other designs.

[0070] Antenna films, like heating films, are films on which antennas such as FM, AM, DTV, and DAB are arranged on the aforementioned base film.

[0071] A dimmable film (dimmable layer) is a film that can change the visibility from outside the vehicle by switching its linear transmittance. Various types of dimmable films have been proposed, but for example, one can control the haze rate of the film by the presence or absence of electricity, creating a transparent state and an opaque state. In other words, it is a functional film that can provide privacy. For example, known types such as PDLC (Polymer Dispersed Liquid Crystal) type, SPD (Suspended Particle Device) type, electrochromic type, and thermochromic type can be used. For example, a PDLC type dimmable film can be composed of a liquid crystal layer, a pair of transparent conductive films sandwiching this liquid crystal layer, and a PET film placed on the outer surface of each transparent conductive film. The liquid crystal layer has a liquid crystal capsule formed by encapsulating a transparent polymer film and liquid crystal. Dimmable films are suitably used, for example, on roof windows.

[0072] The above is merely an example of functional layer 133, and is not limited to these examples.

[0073] The thickness of the film constituting the functional layer 133 described above is not particularly limited, but is preferably 50 to 600 μm, more preferably 50 to 500 μm, and particularly preferably 50 to 100 μm.

[0074] Furthermore, the functional layer 133 has a rectangular through-hole (transparent region) 130 formed therein, which is positioned to correspond to the opening 43 of the shielding layer 4, which will be described later. More specifically, as shown in Figures 1 and 2, the outer edge of this through-hole 130 is located outside the outer edge of the opening 43 of the shielding layer 4, but inside the outer edge of the extended portion 42 of the shielding layer 4.

[0075] The thickness of each adhesive layer 131, 132 and functional layer 133 can be measured, for example, as follows. First, the cross-section of the windshield is magnified 175 times using a microscope (for example, a VH-5500 manufactured by Keyence Corporation) and displayed. Then, the thickness of each adhesive layer 131, 132 and functional layer 133 is identified visually and measured. In this case, in order to eliminate visual variation, the measurement is taken five times, and the average value is taken as the thickness of each adhesive layer 131, 132 and functional layer 133.

[0076] The size of each adhesive layer 131, 132 is the same as that of the outer glass plate 11 and the inner glass plate 12, but the size of the functional layer 133 can be the same as or smaller than that of both adhesive layers 131, 132. For example, the periphery of the functional layer 133 can be positioned inward from the periphery of each glass plate 11, 12, and in particular, it can be positioned so as to be hidden by the periphery 41 of the shielding layer 4, which will be described later.

[0077] The method for manufacturing the interlayer 13 is not particularly limited, but examples include a method in which a resin component such as the polyvinyl acetal resin mentioned above, a plasticizer, and other additives as needed are blended and kneaded uniformly, and then each layer is extruded and molded all at once, or a method in which two or more resin films created by this method are laminated by a pressing method, a laminating method, etc. The resin film used in the lamination method by pressing method, a laminating method, etc., before lamination may have a single-layer structure or a multi-layer structure. In addition, the interlayer 13 can be formed as a single layer, as well as as multiple layers as described above.

[0078] <1-3. Physical Properties of Laminated Glass> Next, the preferred physical properties of laminated glass will be described. (1) Visible Light Transmittance YA In order to use laminated glass as a windshield or side window, YA must be 70.0% or higher (Article 39, Paragraph 3, Item 7 of the Notification Specifying the Details of Safety Standards for Road Vehicles), preferably 70.5% or higher, and more preferably 72.0% or higher. However, if YA is too high, the solar radiation transmittance (Ttf) may decrease, so it is preferable that YA be 75.0% or lower, and more preferably 73.0% or lower. In order to achieve YA of 70% or higher, either of the glass plates in Example 1 and Example 2 described above can be used.

[0079] (2) CIE standard chromaticity b* As described above, since a bluish color is preferred for automotive window glass, the chromaticity b* is preferably 2.0 or less, and more preferably 1.5 or less. To achieve this, for example, a glass plate like at least one of Example 1 or Example 3 described above can be used as either the outer glass plate 11 or the inner glass plate 12.

[0080] (3) Thermal transmittance (Ttf) The thermal transmittance is calculated as described above, but the thermal transmittance (Ttf) of the laminated glass should be about 44% or less, preferably 42% or less, and more preferably 40% or less. This makes it possible to prevent people from feeling too hot, as described above. To achieve this, for example, glass plates like at least one of Example 1 or Example 2 described above can be used for the outer glass plate 11 and the inner glass plate 12.

[0081] <1-4. Others> Various functional films can be laminated onto the interior surface of the inner glass panel 12, for example, a LowE film can be laminated. Also, if it is desired to enhance the ultraviolet absorption performance, an ultraviolet absorbing film can be laminated onto the exterior surface of the outer glass panel 11.

[0082] <2. Overview of the Shielding Layer> Next, the shielding layer 4 will be described. As shown in Figure 1, the shielding layer 4 is laminated on the interior surface of the outer glass plate 11 and on the interior surface of the inner glass plate 12. Since the shielding layer 4 laminated on each of these surfaces has the same shape, the shielding layer 4 laminated on the inner glass plate 12 will be described below. More specifically, this shielding layer 4 comprises a peripheral portion 41 that is laminated along the entire circumference of the periphery of the inner glass plate 12, and a rectangular extension portion 42 that is connected to the peripheral portion 41 and extends downward from near the center of the upper edge of the inner glass plate 12. A trapezoidal opening 43 is formed at the lower end of the extension portion 42, and the photographing device 2 installed on the interior side of the vehicle can photograph the outside of the vehicle through this opening 43 and the laminated glass 10.

[0083] As shown in Figure 2, the bracket 6 described above is fixed onto the shielding layer 4. Specifically, the bracket 6 is formed in a frame shape that surrounds the opening and is fixed to the shielding layer 4 with double-sided tape, adhesive, etc. The camera device 2 is supported by this bracket 6 and is configured to photograph the outside of the vehicle through the opening 43. Although not shown in the figure, a cover is attached to the bracket 6 so that the camera device 2 is not visible from inside the vehicle.

[0084] Next, the material of the shielding layer 4 will be described. The material of the shielding layer 4 may be appropriately selected according to the embodiment, as long as it can block the view from outside the vehicle. For example, dark-colored ceramics such as black, brown, gray, or dark blue may be used.

[0085] If black ceramic is selected as the material for the shielding layer 4, for example, black ceramic is laminated onto the inner surface of the inner glass plate 12 by screen printing or the like, and the ceramic laminated together with each glass plate 11, 12 is heated. When the ceramic hardens, the shielding layer 4 is completed. Various materials can be used for the ceramic used in each shielding layer 4. For example, ceramics with the compositions shown in Table 1 below can be used for the shielding layer 4.

[0086] *1 Main components: copper oxide, chromium oxide, iron oxide, and manganese oxide *2 Main components: bismuth borosilicate, zinc borosilicate

[0087] In the example above, the shielding layer 4 is laminated on the inner surface of the outer glass plate 11 and the inner surface of the inner glass plate 12. However, for example, the shielding layer 4 can also be laminated only on the inner surface of the inner glass plate 12. Alternatively, the shielding layer 4 can also be laminated only on the inner surface of the outer glass plate 11.

[0088] <3. In-vehicle system> Next, an in-vehicle system comprising a camera 2 and an image processing device 3 will be described using Figures 2 and 4. Figure 4 illustrates the configuration of the in-vehicle system. As illustrated in Figure 4, the in-vehicle system according to this embodiment comprises the camera 2 and an image processing device 3 connected to the camera 2.

[0089] The image processing device 3 is a device that processes images acquired by the imaging device 2. For example, the image processing device 3 has a general hardware configuration, such as a storage unit 31, a control unit 32, and an input / output unit 33, all connected by a bus. However, the hardware configuration of the image processing device 3 is not limited to this example, and the specific hardware configuration of the image processing device 3 can be appropriately modified, with components being added, omitted, or added as appropriate, depending on the embodiment.

[0090] The storage unit 31 stores various data and programs used in the processing performed by the control unit 32 (not shown). The storage unit 31 may be implemented by, for example, a hard disk or by a recording medium such as a USB memory. Furthermore, the various data and programs stored in the storage unit 31 may be obtained from a recording medium such as a CD (Compact Disc) or DVD (Digital Versatile Disc). In addition, the storage unit 31 may also be called an auxiliary storage device.

[0091] As described above, the laminated glass 10 is positioned at an inclined angle to the vertical and is curved. The imaging device 2 then photographs the situation outside the vehicle through such laminated glass 10. Therefore, the images acquired by the imaging device 2 are deformed according to the orientation, shape, refractive index, optical defects, etc. of the laminated glass 10. In addition, aberrations inherent to the camera lens of the imaging device 2 are also added. Therefore, the memory unit 31 may store correction data for correcting images deformed by such aberrations of the laminated glass 10 and the camera lens.

[0092] The control unit 32 includes one or more processors, such as a microprocessor or CPU (Central Processing Unit), and peripheral circuits (ROM (Read Only Memory), RAM (Random Access Memory), interface circuits, etc.) used for processing by this processor. The ROM, RAM, etc. may also be called main memory in the sense that they are located in the address space handled by the processor within the control unit 32. The control unit 32 functions as an image processing unit 321 by executing various data and programs stored in the storage unit 31.

[0093] The image processing unit 321 processes the captured image acquired by the shooting device 2. The processing of the captured image can be appropriately selected depending on the embodiment. For example, the image processing unit 321 may recognize subjects in the captured image by analyzing the image using pattern matching or the like. In this embodiment, since the shooting device 2 captures the situation in front of the vehicle, the image processing unit 321 may further determine, based on the subject recognition, whether or not there are living beings such as humans in front of the vehicle. If a person is captured in front of the vehicle, the image processing unit 321 may output a warning message in a predetermined manner. Alternatively, for example, the image processing unit 321 may apply a predetermined processing to the captured image. The image processing unit 321 may then output the processed captured image to a display device (not shown), such as a display connected to the image processing device 3.

[0094] The input / output unit 33 is one or more interfaces for sending and receiving data with devices located outside the image processing device 3. The input / output unit 33 is, for example, an interface for connecting to a user interface, or an interface such as USB (Universal Serial Bus). In this embodiment, the image processing device 3 connects to the imaging device 2 via the input / output unit 33 and acquires images captured by the imaging device 2.

[0095] Such an image processing device 3 may be a device specifically designed for the service being provided, or it may be a general-purpose device such as a PC (Personal Computer) or a tablet terminal.

[0096] Furthermore, as described above, the imaging device 2 is attached to the bracket 6. Therefore, in this state, the attachment of the imaging device 2 to the bracket 6 and the attachment of the bracket to the first shielding layer 4 are adjusted so that the optical axis of the camera lens of the imaging device 2 passes through the opening 43. A cover, not shown in the illustration, is attached to the bracket 6 so as to cover the imaging device 2. Thus, the imaging device 2 is placed in a space enclosed by the laminated glass 10, the bracket, and the cover, so as not to be seen from inside the vehicle, and from outside the vehicle, only a part of the imaging device 2 is visible through the opening 43 by the first and second shielding layers 4 and 5. The imaging device 2 and the input / output unit 33 described above are connected by a cable, not shown in the illustration, which is pulled out from the cover and connected to the image processing device 3 located at a predetermined position inside the vehicle.

[0097] <4. Method for Manufacturing a Windshield> Next, an example of a method for manufacturing a windshield configured as described above will be explained. First, the method for manufacturing the laminated glass 10 will be explained.

[0098] First, the shielding layer 4 described above is laminated onto at least one of the flat outer glass plate 11 and the inner glass plate 12. Next, these glass plates 11 and 12 are shaped to be curved. The shaping method is not particularly limited, and known methods can be used. For example, the flat glass plates can be shaped into a curved form by passing them through a heating furnace and then pressing them with an upper and lower die. Alternatively, the flat outer glass plate and the inner glass plate can be stacked, placed on a frame-shaped mold, and passed through a heating furnace. This softens both glass plates, and they are shaped into a curved form by their own weight.

[0099] Once the outer glass plate 11 and the inner glass plate 12 are formed into a curved shape, the interlayer 13 is then sandwiched between the outer glass plate 11 and the inner glass plate 12, placed in a rubber bag, and pre-bonded at approximately 70-110°C under reduced pressure suction. The interlayer 13 is, for example, a functional layer 133 with through holes 130 sandwiched between adhesive layers 131 and 132. Other pre-bonding methods are also possible. For example, the interlayer 13 is sandwiched between the outer glass plate 11 and the inner glass plate 12 and heated in an oven at 45-65°C. Subsequently, this laminated glass is pressed with a roller at 0.45-0.55 MPa. Next, this laminated glass is heated again in an oven at 80-105°C, and then pressed again with a roller at 0.45-0.55 MPa. Thus, pre-bonding is completed.

[0100] Next, the final bonding is performed. The pre-bonded laminated glass is then bonded in an autoclave, for example, at 8 to 15 atmospheres and 100 to 150 degrees Celsius. Specifically, for example, the final bonding can be performed at 14 atmospheres and 145 degrees Celsius. In this way, the windshield according to this embodiment is manufactured.

[0101] <5. Features> In the windshield configured as described above, at least one of the outer glass plate 11 and the inner glass plate has infrared absorption properties, which helps to suppress the feeling of temperature differences among occupants. Furthermore, since one of the glass plates 11 or 12 has infrared absorption properties, it is not necessary for the interlayer 13 to have that function. Therefore, other functions can be added to the interlayer 13.

[0102] <6. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. The following modifications can be combined as appropriate. Furthermore, each of the following modifications can be combined with the above embodiment as appropriate.

[0103] <6-1> In the above embodiment, the interlayer 13 is configured such that the functional layer 133 is sandwiched between the first and second adhesive layers 131 and 132. However, the adhesive layer can also be placed on only one side of the functional layer 133. In this case, the functional layer 133 will be bonded to one glass plate, and the adhesive layer will be bonded to the other glass plate.

[0104] <6-2> The shape of the shielding layer 4 is not particularly limited, and various shapes are possible. That is, it is sufficient that at least one opening 43 for photography is formed, and the shape of the opening is not particularly limited. Therefore, two or more openings may be formed.

[0105] <6-3> In the above embodiment, visible light is directed into the camera of the imaging device through the opening. However, devices other than the imaging device may be placed on the windshield of the above embodiment to acquire information from outside the vehicle. For example, devices that acquire various electromagnetic waves other than visible light, such as infrared sensors, infrared cameras, and optical beacons, may be used.

[0106] <6-4> In the above embodiment, an example of applying the automotive window glass according to the present invention to a windshield has been described, but it is not limited to this, and as mentioned above, it can also be applied to rear windows, side windows, roof windows, etc. In this case, a shielding layer having an opening as described above is not necessary, and a shielding layer may be provided if necessary. When using the window glass of the present invention as a windshield, for example, the window glass can be formed to extend above the driver's head. That is, it can be a window glass that combines a windshield and a roof window.

[0107] The following describes embodiments of the present invention. However, the present invention is not limited to the following embodiments.

[0108] <1. Window Glass According to Examples and Comparative Examples> Below, window glass according to Examples 1 to 3 and window glass according to the comparative examples were prepared. Each window glass has an outer glass plate, an inner glass plate, and an interlayer placed between these glass plates. Here, each window glass was constructed using the following three glass plates. Table 3 shows the composition of each glass plate (unit is mass%). Table 4 shows the physical properties of each glass plate. Each physical property is as described in the above embodiments. However, Tuv refers to Tuv ISO 9050-2003.

[0109] A 0.76 mm thick polyvinyl butyral interlayer (without coloring elements) was prepared as an interlayer. This interlayer was used for all the window panes. Glass plates 1 and 2 correspond to the glass plates in Examples 1 and 2 described above, respectively.

[0110] <2. Consideration of Each Glass Plate> Comparing glass plates 1 and 2, glass plate 2 has a slightly higher FeO and Fe2O3 content than glass plate 1. As a result, the Ttf of glass plate 2 is slightly lower than that of glass plate 1, and the YA of glass plate 2 is also slightly lower than that of glass plate 1. On the other hand, the total TiO2 and CeO2 content of glass plate 2 is higher than that of glass plate 1. As a result, the Tuv of glass plate 2 is lower than that of glass plate 1, but the chromaticity b* of glass plate 2 is higher than that of glass plate 1.

[0111] Glass plate 3 has a lower Fe2O3 content than glass plates 1 and 2. As a result, the Ttf and Tuv of glass plate 3 are higher than those of glass plates 1 and 2, but the chromaticity b* is lower. This is partly due to the lower total TiO2 and CeO2 content of glass plate 3. Furthermore, glass plate 3 has the highest YA due to this composition.

[0112] Furthermore, glass plate 1 has a Tuv / Ttf of 0.5 or higher, resulting in a high YA and low Ttf. On the other hand, glass plate 2 has a Tuv / Ttf of less than 0.5, so while its Ttf is low, its YA is somewhat low. However, because its Tuv is low, its UV absorption performance is high.

[0113] <3. Fabrication of Window Glass> Using the glass plates and interlayers described above, window glass according to Examples 1 to 3 and the Comparative Example was fabricated as follows.

[0114] The glass plates constituting each window pane are shown in Table 5 below (the upper row shows the outer glass plate, and the lower row shows the inner glass plate). The physical properties of each window pane are shown in Table 4. Table 6 shows the physical properties of Examples 1 to 3 and the comparative example.

[0115] <4. Evaluation> The window glass according to Examples 1 to 3 and the comparative example described above was evaluated for visible light transmittance, deterioration of the interlayer, and color.

[0116] <4-1. Visible Light Transmittance> Visible light transmittance was evaluated as follows based on the YA of the window glass shown in Table 6: A: YA is 72.0 or higher B: YA is less than 72.0

[0117] <4-2. Infrared (IR) Cut Performance> The following was evaluated using Ttf: A: 44% or less B: Higher than 44%

[0118] <4-3. Color> Evaluated based on chromaticity b*. A: Bluish color (chromaticity b* less than 1.5). B: Color between A and B (slightly yellowish) (chromaticity b* 1.5 or more and less than 3.0). C: Yellowish color (chromaticity b* 3.0 or more).

[0119] <4-4. Results> The results are shown in Table 7.

[0120] <4-4-1. Regarding infrared absorption performance (IR cut performance)> The comparative example has a Ttf of over 50%, so it can be said to have low IR cut performance. On the other hand, Examples 1 to 3 have a Ttf of 44% or less, so they can be said to have high IR cut performance.

[0121] Examples 1 to 3 obtained the above A rating because they used either glass plate 1 or 2 with a low Ttf.

[0122] <4-4-2. Visible Light Transmittance> Visible light transmittance is primarily determined by the YA (Yield Absorption) ratio. As shown in Table 6, the YA of Example 1 is 72.0% or higher, making it suitable for use as a windshield and side window. However, the YA of Examples 2 and 3 both exceed the 70% required for windshields and side windows. Therefore, Examples 1 to 3 can be used as windshields and side windows.

[0123] <4-4-3. Regarding Color> As mentioned above, a bluish color is often required for automobile windows, so Example 1, which has an evaluation of A, can be suitably used in vehicles. In Example 1, the chromaticity b* is 2 or less, which is because glass plates 1 with a chromaticity b* of 1 or less are used as the outer and inner glass plates.

[0124] Example 3, which received a rating of B, has a chromaticity b* of 2 to 3 and is slightly yellowish, but not as yellowish as a rating of A, and can be used in vehicles. In Example 3, either the outer glass plate or the inner glass plate is made of glass plate 1 with a chromaticity b* of 1 or less.

[0125] Example 2, which received a rating of C, has a chromaticity b* of 3 or higher and a yellowish appearance. While this is not ideal, it does not mean that it cannot be used in vehicles. Example 2 uses glass plates 2 in which both the outer and inner glass plates have a chromaticity b* of 1.5 or higher, which is likely why the chromaticity b* is high.

[0126] 11. Outer glass plate 12. Inner glass plate 13. Interlayer

Claims

1. Automotive window glass comprising an outer glass plate, an inner glass plate, and an interlayer that bonded the outer glass plate and the inner glass plate and substantially had no infrared absorption properties, wherein the thermal transmittance (Ttf) is 44.0% or less.

2. The automotive window glass according to claim 1, wherein the chromaticity b* according to the CIE standard is 2.0 or less.

3. The automotive window glass according to claim 1, wherein the chromaticity b* according to the CIE standard is 1.5 or less.

4. The automotive window glass according to claim 1, wherein the visible light transmittance YA, measured in accordance with JIS R3106:1998 using a CIE standard A light source, is 72.0% or higher.

5. The automotive window glass according to claim 1, wherein at least one of the outer glass plate and the inner glass plate contains t-Fe2O3, which is the total iron oxide content converted to Fe2O3, at a rate of 0.60% by mass or more, and the sum of CeO2 and TiO2 is 0.10% by mass or less, and the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3 converted to Fe2O3, is 25% or more.

6. The automotive window glass according to claim 1, wherein both the outer glass plate and the inner glass plate contain t-Fe2O3, which is the total iron oxide content converted to Fe2O3, at a rate of 0.60% by mass or more, and the sum of CeO2 and TiO2 is 0.05% by mass or less, and the FeO ratio, which is expressed as the mass ratio of FeO to t-Fe2O3 converted to Fe2O3, is 25% or more.

7. The automotive window glass according to claim 1, wherein at least one of the outer glass plate and the inner glass plate has a visible light transmittance YA of 81.5% or more and 83.5% or less, and a Tuv (ISO 9050-2003) of 0.5 or more relative to the thermal transmittance.

8. The automotive window glass according to claim 1, wherein both the outer glass plate and the inner glass plate have a visible light transmittance YA of 81.5% or more and 83.5% or less, and a Tuv (ISO 9050-2003) of 0.5 or more relative to the thermal transmittance.

9. A windshield using the automobile window glass described in claim 1.

10. The windshield according to claim 9, which extends above the driver's seat.

Images