Patent ID: 12227057

DESCRIPTION OF EMBODIMENTS

First, a configuration of a windshield according to the present embodiment will be described with reference toFIGS.1and2.FIG.1is a plan view of windshield according to the present embodiment, andFIG.2is a cross-sectional view ofFIG.1. For convenience of explanation, the vertical direction inFIG.1may be referred to as a “top-bottom”, “vertical”, or “longitudinal” direction, and the horizontal direction inFIG.1may be referred to as a “left-right” direction.

As shown inFIG.1, the windshield is provided with a laminated glass10that has a trapezoidal shape that is elongated in the horizontal direction. This laminated glass10includes an outer glass plate11, an inner glass plate12, and an intermediate film13disposed therebetween. An obstructing layer4is laminated on a peripheral edge portion of the vehicle interior-side surface of the inner glass plate12so as to obstruct the field of view from the outside of the vehicle. The following describes each constituent elements in detail.

<1. Laminated Glass>

<1.1. Glass Plates>

First, the outer glass plate11and the inner glass plate12will be described. The glass plates11and12can be known glass plates, and can also be formed with heat absorbing glass, ordinary clear glass or green glass, or UV green glass. However, these glass plates11and12need to achieve visible light transmittance conforming to the safety standards in the country in which an automobile is used. For example, an adjustment can be made so that a required solar absorptivity is ensured in the outer glass plate11, and the visible light transmittance satisfies the safety standards with the inner glass plate12. Examples of clear glass, heat absorbing glass, and soda-lime glass are listed below.

Clear Glass

SiO2: 70 to 73 mass %Al2O3:0.6 to 2.4 mass %CaO: 7 to 12 mass %MgO: 1.0 to 4.5 mass %R2O: 13 to 15 mass % (R denotes alkali metal)Total iron oxide (T-Fe2O3) expressed in terms of Fe2O3: 0.08 to 0.14 mass %
Heat Absorbing Glass

The composition of heat absorbing glass can be, for example, a composition that is based on the composition of clear glass, where the proportion of total iron oxide (T-Fe2O3) expressed in terms of Fe2O3is 0.4 to 1.3 mass %, the proportion of CeO2is 0 to 2 mass %, the proportion of TiO2is 0 to 0.5 mass %, and the skeletal component (primarily, SiO2and Al2O3) of glass is reduced by the increased amount of T-Fe2O3, CeO2, and TiO2.

Soda-lime Glass

SiO2: 65 to 80 mass %Al2O3: 0 to 5 mass %CaO: 5 to 15 mass %MgO: 2 mass % or moreNaO: 10 to 18 mass %K2O: 0 to 5 mass %MgO+CaO: 5 to 15 mass %Na2O+K2O: 10 to 20 mass %SO3: 0.05 to 0.3 mass %B2O3: 0 to 5 mass %Total iron oxide (T-Fe2O3) expressed in terms of Fe2O3: 0.02 to 0.03 mass %

Although the thickness of the laminated glass10according to the present embodiment is not particularly limited, the total thickness of the outer glass plate11and the inner glass plate12is preferably 2.1 mm to 6 mm. From the viewpoint of weight reduction, the total thickness of the outer glass plate11and the inner glass plate12is preferably 2.4 mm to 3.8 mm, more preferably 2.6 mm to 3.4 mm, and particularly preferably 2.7 mm to 3.2 mm.

The outer glass plate11principally needs durability and shock resistance against an external obstacle. When used as an automobile windshield, the outer glass plate11needs shock resistance against a flying object, such as a small stone. Meanwhile, the larger the thickness is, the larger the weight is, which is not favorable. From this viewpoint, the thickness of the outer glass plate11preferably is 1.8 mm to 2.3 mm, and more preferably is 1.9 mm to 2.1 mm. The thickness to be employed can be determined in accordance with the usage of the glass.

The thickness of the inner glass plate12can be made equal to that of the outer glass plate11, but can alternatively be made smaller than the thickness of the outer glass plate11for the reduction in the weight of the laminated glass10, for example. Specifically, giving consideration to the glass strength, the thickness of the inner glass plate12is preferably 0.6 mm to 2.0 mm, more preferably 0.8 mm to 1.6 mm, and particularly preferably 1.0 mm to 1.4 mm. Furthermore, the thickness of the inner glass plate12is preferably 0.8 mm to 1.3 mm. The thickness of the inner glass plate12to be employed can also be determined in accordance with the usage of the glass.

In addition, the laminated glass10is curved so as to protrude toward the outside of the vehicle as described later in detail, and the thickness in such a case is measured at two positions, namely an upper position and a lower position on a center line (a curved line OP described below) that extends in the top-bottom direction passing through the center of the laminated glass10in the left-right direction. There is no particular restriction on the type of measurement instrument, but a thickness gauge, such as the SM-112 manufactured by Teclock Corporation for example, can be used. During measurement, the laminated glass10is arranged so that the curved face thereof is placed on a flat face, and measurement is performed while holding an end portion of the laminated glass1using the aforementioned thickness gauge.

<1-2. Intermediate Film>

As shown inFIG.2, the intermediate film13includes a first adhesion layer131that is transparent and is bonded to the outer glass plate11, a second adhesion layer132that is transparent and is bonded to the inner glass plate12, and a functional layer133that is transparent and is disposed between the adhesion layers131and132.

Although the first adhesion layer131and the second adhesion layer132are not particularly limited as long as they can be bonded to the glass plates11and12, they may be formed of, for example, polyvinyl butyral resin (PVB), ethylene vinyl acetate (EVA), or the like. Generally, it is possible to control the hardness of a polyvinyl acetal resin by controlling (a) the degree of polymerization of polyvinyl alcohol that is a starting material, (b) the degree of acetalization, (c) the type of plasticizer, (d) the addition ratio of the plasticizer, and so on.

The surfaces of the first adhesion layer131and the second adhesion layer132before being bonded to the glass plates11and12may be embossed in order to easily push air out when the first adhesion layer131and the second adhesion layer132are bonded to the functional layer133or to the glass plates11and12.

Although the thicknesses of the first adhesion layer131and the second adhesion layer132are not particularly limited, the thicknesses are preferably 20 μm to 2.0 mm, more preferably 20 μm to 1.0 mm, and particularly preferably 50 μm to 100 μm. Note that the thicknesses of the adhesion layers131and132may be the same or different. When the adhesion layers131and132are to be embossed, it is preferable to set the thickness to 20 μm or more as described above, considering the embossing depth. Also, instead of using a sheet-shaped adhesive layer, it is possible to form the adhesion layers131and132through coating. In such a case, it is possible to form a thin adhesion layer of 0.3 μm to 100 μm.

The total thickness of the adhesion layers131and132is preferably no less than 0.76 mm. This is to ensure the penetration resistance and the like of the windshield, specified in JIS R3211 and R3212, for example.

A film having various functions can be used as the functional layer133according to the purpose. For example, a known heat shield film, heat generating film, projection film, light emitting film, antenna film, or the like may be used.

In order to suppress a temperature rise in the vehicle, a known infrared reflective film that reflects infrared rays, or a film configured to absorb infrared rays may be adopted as the heat shield film. Such a heat shield film is preferably disposed on the outer glass plate11side in the thickness direction of the intermediate film13. That is to say, the first adhesion layer131is to be thinner than the second adhesion layer132. With such a configuration, the laminated glass can absorb infrared rays at a position farther from the vehicle interior. In order to achieve a heat shielding function, in addition to forming the functional layer133using a heat shield film, it is possible to form at least either the first adhesion layer131or the second adhesion layer132using a heat shielding PVB.

The heat generating film is used to remove fogging and to deice, and has a configuration in which a plurality of thin wires that generate heat upon a voltage being applied thereto are supported by a base film. The base film may be a transparent film, and the material thereof is not particularly limited. The base film may be formed of, for example, polyethylene terephthalate, polyethylene, polymethylmethacrylate, polyvinyl chloride, polyester, polyolefin, polycarbonate, polystyrene, polypropylene, nylon, or the like.

The projection film is a film to which information is projected by light emitted from a head-up display device (hereinafter referred to as an HUD). The projection film is not particularly limited as long as it is a film that reflects light and has a refractive index different from those of the adhesion layers131and132. For example, a film that can control polarization, such as a p-polarized light reflection film, a hologram film, a scattering reflection system type transparent screen, a scattering transmission type transparent screen, a scattering reflection type dimming film, a scattering transmission type dimming film, or a high reflection film for an HUD may be used. Although the size of the projection film is not particularly limited, it is preferably larger than the area to which information is to be projected. The projection film may be supported by a base film. The base film may be the same as the aforementioned heat generating film. The projection film may have the same size as the base film, or smaller than the base film. If this is the case, it is preferable that the outer edge of the projection film is located inward of the outer edge of the base film.

Note that the base film may be disposed on either the outer glass plate-side surface or the inner glass plate-side surface of the projection film. Alternatively, the projection film may be sandwiched between two base films.

The light emitting film has a built-in LED or the like, and emits light to show predetermined characters, figures, and so on.

The antenna film is, as with the heat generating film, a film formed by disposing an FM, AM, DTV, or DAB antenna on the above-described base film, for example.

Note that the above-described films are examples of the functional layer133, and the functional layer133is not limited to these examples.

Although not particularly limited, the thickness of the film constituting the functional layer133described above is preferably 0.01 mm to 2.0 mm, and more preferably 0.03 mm to 0.6 mm, for example. As described above, the upper limit of the thickness of the end face of a peripheral edge portion of the film is preferably 2.0 mm. When the thickness of the end face of the film is large, the functional layer133is smaller than the two adhesion layers131and132, and therefore a step is formed in the interlayer film13. Due to this step, when the intermediate film13is sandwiched between the two glass plates11and12, air may be contained and bubbles may be formed.

In order to prevent wrinkles from being formed, it is preferable that the functional layer133appropriately shrinks when heated at the time of bonding. The heat shrinkage rate of the functional layer133is preferably small, and is preferably no greater than 4% when heated at 130° C. for 30 minutes, for example. In particular, when a projection film is used as the functional layer133, the heat shrinkage is preferably no greater than 1% when heated at 130° C. for 30 minutes. This is because a heat shrinkage rate that is too large causes image distortion, for example. The heat shrinkage can be measured in the following manner. First, a film having the functional layer133is provided with marks at intervals of 500 mm, this film is placed on a substrate without being fixed thereto, and is held in an electric furnace kept at 130° C., for 30 minutes, and the distance between the marks is measured to calculate the heat shrinkage.

The heat shrinkage of the functional layer133described above is that before the windshield is manufactured. However even after the windshield is manufactured as described below, the functional layer133obtained by disassembling the windshield preferably shrinks under the above-described conditions.

Note that the thicknesses of the adhesion layers131and132and the functional layer133can be measured in the following manner, for example. First, the cross section of the windshield is magnified 175 times and displayed, using a microscope (for example, VH-5500 manufactured by KEYENCE). Thereafter, the thicknesses of the adhesion layers131and132and the functional layer133are visually specified, and are measured. At this time, in order to eliminate visual variations, the number of measurements is set to 5, and the average value is taken as the thicknesses of the adhesion layer131and132and the functional layer133.

The adhesion layers131and132have the same size as the outer glass plate11and the inner glass plate12, whereas the functional layer133has a smaller size than the adhesion layers131and132. Specifically, the peripheral edge of the functional layer133is located inward of the peripheral edges of the glass plates11and12. For example, the peripheral edge of the functional layer133is preferably located at a position that is 5 mm or more inward of the peripheral edges of the glass plates11and12, and more preferably at a position that is 10 mm or more inward thereof. This is to prevent water from entering from the edge of the intermediate film13when wrinkles are formed at the edge of the functional layer133as described later.

<2. Obstructing Layer>

As shown inFIG.1, the obstructing layer4of a dark-color ceramic such as a black ceramic is laminated on the periphery of the windshield. The obstructing layer4is used to obstruct the field of view from the inside or the outside of the vehicle, is laminated along the four sides of the windshield, and is configured to cover a peripheral edge portion of the functional layer133. Therefore, as described below, the obstructing layer4can hide a peripheral edge portion of the functional layer133, which is likely to have wrinkles, and hide this part so as to be invisible from the inside or the outside of the vehicle.

As described above, the obstructing layer4may be laminated on various modes. For example, in addition to being laminated only on the vehicle interior-side surface of the inner glass plate12, the obstructing layer4may be laminated only on the inner surface of the outer glass plate11, or on the inner surface of the outer glass plate11and the inner surface of the inner glass plate12. In addition, the obstructing layer4may be formed of various materials. For example, the following compositions may be employed.

TABLE 1First and SecondColored Ceramic PastePigment *1mass %10Resin (Cellulosicmass %10Resin)Organic Solventmass %10(Pine Oil)Glass Binder *2mass %70ViscositydPs150*1, Main ingredients: copper oxide, chromium oxide, iron oxide, and manganese oxide*2, Main ingredients: bismuth borosilicate, zinc borosilicate

The ceramic can be formed by means of screen printing, but can also be manufactured by transferring a transfer film for firing onto a glass plate and firing this glass plate. In the case of employing screen printing, for example, the following conditions may be employed: polyester screen: 355 mesh, coat thickness: 20 μm, tension: 20 Nm, squeegee hardness: 80 degrees, attachment angle: 75°, and printing speed: 300 mm/s, and the ceramic can be formed after being dried in a drying oven at 150° C. for 10 minutes.

Note that the obstructing layer4can be formed not only by laminating a ceramic, but also by attaching an obstructing film that is made of a dark-color resin.

<3. Relationship Between Curve of Glass Plates and Intermediate Film>

As described above, the windshield according to the present embodiment is curved so as to protrude toward the outside of the vehicle. Here, the relationship between the curve of the glass plates and the intermediate film will be examined. As shown inFIGS.3to5, the dimensions and physical properties of the windshield are defined as follows. Note thatFIG.3is a perspective view of the windshield according to the present embodiment,FIG.4is a cross-sectional view taken along the line OP inFIG.3, andFIG.5is a cross-sectional view taken along a line QR inFIG.3.

The midpoint of the upper side of the inner glass plate: O

The midpoint of the lower side of the inner glass plate: P

The midpoint of the left side of the inner glass plate: Q

The midpoint of the right side of the inner glass plate: R

The length of a curved line OP extending along the vehicle interior-side surface (a first surface) of the inner glass plate: LV

The length of a straight line OP: IV

The length of a curved line QR extending along the first surface of the inner glass plate: Lh

The length of a straight line QR: IH

IV/LV: rV

IH/LH: rH

A roll winding direction in which the functional layer is fed out: an MD direction

A direction that is orthogonal to the roll winding direction in which the functional layer is fed out: a TD direction

The heat shrinkage of the functional layer in the MD direction before and after being heated at 130° C. for 30 minutes: rMD

The heat shrinkage of the functional layer in the TD direction before and after being heated at 130° C. for 30 minutes: rTD

As shown inFIG.3, the windshield has a shape in which the line extending in the vertical direction (the Y axis) connecting the above-described points O and P is curved, and the line extending in the horizontal direction (the X axis) connecting the above-described points Q and R is curved. That is to say, this windshield has a three-dimensional structure. In the following description, the maximum distance between the straight line OP and the vehicle interior-side surface of the inner glass plate12is referred to as an amount of bend d, and the maximum distance between the straight line QR and the vehicle interior-side surface of the inner glass plate12is referred to as a bending depth y. In the windshield targeted by the present embodiment, the amount of bend d and the bending depth y, which indicate the degree of curvature, are both no less than 10 mm, and as a result, the functional layer133is likely to have wrinkles as described below.

By the way, as described below, the intermediate film13is disposed between the outer glass plate11and the inner glass plate121, and is fixed between the two glass plates11and12after heat and pressure are applied thereto. At this time, mainly the adhesion layers131and132melt, but the functional layer133does not melt. In addition, the two glass plates11and12are curved in both the horizontal direction and the vertical direction, when the flat intermediate film13is disposed and bonded between the two glass plates11and12, wrinkles may be formed on a peripheral edge portion of the functional layer133. Therefore, in the present embodiment, studies have been made to prevent wrinkles from being formed on a peripheral edge portion of the functional layer133, as much as possible.

rVand rHare defined in the above definition, which indicate the degree of curvature of the windshield in the axial direction. The larger the values are, the closer to a flat plane the windshield is. In the present embodiment, the above-described flat functional layer133is disposed between the two glass plates11and12that are three-dimensionally curved. However, the functional layer133shrinks because heat is applied thereto at the time of manufacture. Therefore, it can be envisaged that, even if such wrinkles are formed, they will be eliminated or reduced through heat shrinkage, depending on the conditions described below. The inventors of the present invention found that, when the degrees of curvature rVand rHand the heat shrinkages rMDand rTDwere compared with each other, and the degrees of curvature rVand rHwere larger than the heat shrinkages, almost no wrinkles were formed.

Here, in the present embodiment, the intermediate film13is disposed between the two glass plates11and12so that the MD direction coincides with the longitudinal direction of the windshield, i.e., the horizontal direction. The inventors of the present invention found that wrinkles did not occur when Formula (1) below considering the curvature in both the X axis direction and the Y axis direction was satisfied. That is to say, if the degree of curvature of the windshield is greater than the degree of heat shrinkage of the functional layer133, the excessive portion of the functional layer that does not follow the curved surface shrinks due to the heat shrinkage of the functional layer133, and the functional layer133follows the curvature, and wrinkles are less likely to be formed.
rV×rH≥rMD×rTD(1)

Also, when the degree of curvature in the lateral direction is small, i.e., when rVis sufficiently large, wrinkles formed due to the curvature in the lateral direction can be ignored. That is to say, when the intermediate film13is disposed between the outer glass plate11and the inner glass plate12, the functional layer133is disposed so as to match the curvature in the longitudinal direction, and thus wrinkles are prevented from being formed in the longitudinal direction on the functional layer133. Also, since the degree of curvature in the lateral direction is small, the influence of wrinkles on the functional layer133caused due to the curvature in the lateral direction is small. Therefore, the intermediate film13can be disposed between the two glass plates11and12so that the number of wrinkles formed on the functional layer133is reduced, as in the case of wrapping a flat sheet around a columnar object.

Furthermore, when the two glass plates11and12and the intermediate film13are bonded together, if the functional layer133satisfies rV≥rTD, the excessive portion of the functional layer in the lateral direction shrinks due to the heat shrinkage of the functional layer133so as to follow the curvature. As a result, it is possible to dispose the functional layer133while preventing wrinkles from being formed. From the above, the inventors of the present invention found that, when the intermediate film13was to be bonded, if Formula (2) was satisfied, wrinkles were not formed or only negligible wrinkles were formed.
rV≥0.9990 andrV≥rTD(2)

As described above, in order to prevent wrinkles from being formed on the functional layer133, it is preferable to form the laminated glass10so as to satisfy at least one of Formulas (1) and (2), and when both Formulas (1) and (2) are satisfied, it is possible to further prevent wrinkles from being formed.

<4. Method for Manufacturing Windshield>

Next, an example of a method for manufacturing a windshield with the above-described configuration will be described. First, a method for manufacturing a laminated glass1will be described.

First, at least one of the outer glass plate11and the inner glass plate12that have a flat plate shape, and the above-described obstructing layer4are laminated. Next, shape forming is performed so that the glass plates11and12are curved. The shape forming method is not particularly limited, and a known method may be adopted. For example, after the flat glass plates have passed through a heating furnace, by pressing the glass plates using an upper mold and a lower mold, it is possible to form the glass plates into a curved shape. Alternatively, the flat outer glass plate and inner glass plate are placed on each other, are positioned on a frame-shaped mold, and are passed through a heating furnace. As a result, the two glass plates are softened, and are formed into a curved shape due to their own weight.

When the outer glass plate11and the inner glass plate12are formed in a curved shape in this way, the intermediate film13is subsequently sandwiched between the outer glass plate11and the inner glass plate12, and they are placed in a rubber bag, and pre-bonded to each other at approximately 70° C. to 110° C. while performing suction under reduced pressure. The intermediate film13is, for example, the functional layer133sandwiched by the adhesion layers131and132. Other pre-bonding methods may also be employed. For example, the intermediate film13is sandwiched between the outer glass plate11and the inner glass plate12, and they are heated at 45° C. to 65° C. in an oven. Subsequently, this laminated glass is pressed using a roll at 0.45 MPa to 0.55 MPa. Next, the laminated glass is heated again in the oven at 80° C. to 105° C., and is thereafter pressed again using a roll at 0.45 MPa to 0.55 MPa. In this way, pre-bonding is complete.

Next, main bonding is performed. The pre-bonded laminated glass is subjected to main bonding, using an autoclave at 8 atm to 15 atm at 100° C. to 150° C., for example. Specifically, main bonding can be performed at 14 atm at 145° C., for example. Thus, the laminated glass1according to the present embodiment is manufactured.

<5. Features>

With the above-described windshield, the following effects can be achieved.

(1) If a flat intermediate film13is sandwiched between two curved glass plates11and12, wrinkles may be formed on a peripheral edge portion of the functional layer133in the intermediate film13. However, the peripheral edge portion of the functional layer133is hidden by the obstructing layer4, and therefore wrinkles, if formed, are prevented from being seen from the inside or the outside of the vehicle. Thus, it is possible to improve the appearance of the windshield.

(2) The outer edge of the functional layer133is located inward of an end edge of the laminated glass10so as not to be exposed to the outside from the two glass plates11and12. Therefore, at the end edge of the laminated glass10, the portion exposed from the two glass plates11and12is protected by the adhesion layers131and132, and water ingress is prevented.

(3) By satisfying at least one of the above Formulas (1) and (2), it is possible to prevent wrinkles from being formed.

<6. Modifications>

Although one embodiment of the present invention is described above, the present invention is not limited to the above embodiment, and can be modified in various manners without departing from the spirit thereof. Note that the following modifications can be combined as appropriate.

<6-1>

In the above embodiment, the entire outer edge portion of the functional layer133is located inward of the inner edge of the obstructing layer4. However, there is a case in which wrinkles are not formed on the entire outer edge portion of the functional layer133. Therefore, instead of the entire outer edge portion of the functional layer133, a portion thereof may be located outward of the inner edge of the obstructing layer4. However, it is preferable that a portion that faces the upper side of the laminated glass10, of the functional layer133, is located outward of the inner edge of the obstructing layer4. This is because rainwater may enter from the upper side of the laminated glass10, and it is preferable that this portion is hidden by the obstructing layer4.

Furthermore, for example, when a projection film for an HUD is used as the functional layer, a projection film133may be provided at the lower end of the laminated glass as shown inFIG.6. In this case, the projection film133is formed into a rectangular shape. Therefore, it is possible to hide the right side and the lower side of the projection film133with the obstructing layer4. Also, the portion exposed from the obstructing layer4can be made difficult to see by forming a corner portion136at which the upper side and the lower side intersect into an arc shape.

When the projection film133is used, in order to make the information projected from the HUD easier to see, it is preferable to set the visible light transmittance of the inner glass plate12defined by JIS R3106:1998, for example, to be larger than the visible light transmittance of the outer glass plate11. In addition, it is possible to make the visible light transmittance per unit thickness of the inner glass plate12larger than the visible light transmittance per unit thickness of the outer glass plate11. It is also preferable that the thickness of the inner glass plate12is smaller than the thickness of the outer glass plate11. The visible light transmittance of the inner glass plate12is preferably no less than 85%, for example.

In addition, the projection film133is preferably disposed on the inner glass plate12side in the thickness direction of the intermediate film13. That is to say, the second adhesion layer132is to be thinner than the first adhesion layer131. As a result, the optical path from the HUD is reduced, and a double image is less likely to occur. In this case, the distance between the projection film133and the inner glass plate12, i.e., the thickness of the second adhesion layer132is preferably 0.3 μm to 100 μm, and more preferably 5 μm to 100 μm. When the second adhesion layer132is to be thinned, the inner glass plate12side surface of the projection film133may be coated with, for example, a material constituting the second adhesion layer132, such as PVB. As a result, the thickness of the second adhesion layer132, i.e., the distance between the projection film133and the inner glass plate12, can be set to approximately 0.3 μm.

The projection film133can be used alone as a functional layer. However, for example, as shown inFIG.7, the projection film133may be disposed on a base film138, and these films may be disposed between the two adhesion layers131and132. In this example, the projection film133is formed so as to be smaller than the base film138.

If a functional layer that includes the projection film133and the base film138described above is disposed in the laminated glass10, a step may be formed in the intermediate film13due to the presence of the outer edge portion of the functional layer133. As a result, the laminated glass10may bulge in the thickness direction, and a double image larger than a reference size may be formed. In particular, the inventors of the present invention confirmed that the laminated glass is distorted in a predetermined range in the planar direction from the outer edge of the functional layer, i.e., the outer edge of the base film, and such a distortion causes a double image larger than a reference size. Note that, as shown inFIG.7, a double image is formed in both the range from the outer edge of the functional layer133, i.e., an outer edge Q of the base film138to the laminated glass's edge side (X2 side), and the range to the base film side (X1 side), which is the opposite side. Therefore, it is preferable that the projection film133to which light is projected from the HUD is separated from the outer edge of the base film138so that a double image larger than the reference size is not formed. That is to say, through Test 2 described below, it has been confirmed that a distance L1 between the outer edge of the projection film133and the outer edge of the base film is preferably no less than 10 mm, and regarding an image reflected on the projection film, such a configuration prevents a double image from being formed.

In particular, through the Test 1 below, the inventors of the present invention have confirmed that, when a distance d between the functional layer (projection film133) and the inner glass plate12is no greater than 50 μm, a double image can be prevented from being formed on the projection film133by setting the distance L1 to be no less than 26.8 mm. Note that, when the distance d between the functional layer133and the inner glass plate12is no greater than 30 μm, and furthermore, when the distance d is no greater than 25 μm, it is particularly preferable that the distance L1 is no less than 26.8 mm. Note that the distance verified in the above description is based on the above-mentioned knowledge regarding the double image formed on the X1 side, but it has also been confirmed by the inventors that the same applies to the double image formed on the X2 side, i.e., in the direction away from the functional layer133.

The following describes Test 1. Specifically, as schematically shown inFIG.7, the first adhesion layer131, the projection film133with a thickness of 101 μm, and the second adhesion layer132were disposed between the outer glass plate1and the inner glass plate2with a side of 300 mm and a thickness of 2 mm, so as to be laminated in the stated order. Here, the thickness of the intermediate film13was 0.76 mm, and the distance from the projection film133to the inner glass plate12(approximately the thickness of the second adhesion layer132) was 25 μm. The projection film133has a size of 252 mm×268 mm, which is smaller than the base film138, and the distance L1 is secured between the outer edge of the base film138and the outer edge of projection film133. In such a laminated glass, a double image measurement conforming to JIS R3211/R3212 was performed while changing the position of the projection film133on the base film138and changing the distance L1. Specifically, a double image was measured at the outer edge P of the projection film133when the distances L1 were 21 mm, 71 mm, and 121 mm. The results are shown inFIG.8.

FIG.8is a logarithmic graph showing three measurement points and an approximate curve thereof. It was found that a distance L1 that conforms to the reference value defined in the JIS described above, i.e., a distance L1 at which the double image was considered to be no greater than 25 minutes, was 26.8 mm. That is to say, it was found that when the distance L1 from the outer edge of the base film138to the outer edge of the projection film133is no less than 26.8 mm, a double image larger than the reference value would not be formed on the projection film133.

Furthermore, Test 2 described below was also conducted. Through this Test 2, on a laminated glass on which three types of projection films133shown in Table 2, the position of each projection film133was moved, and a double image was measured using the above-described method. The outer glass plate11and the inner glass plate12had a side of 300 mm and a thickness of 2 mm. The thickness of intermediate film13was 0.76 mm. Note that the film2shown in Table 2 below is the same as the projection film used in Test 1 above.

TABLE 2Film 1Film 2Film 3Size236 mm × 266 mm252 mm × 268 mm236 mm × 250 mmThickness103 μm101 μm50 μmDistance L1 from25 μm25 μm380 umOuter Edge ofBase Film toOuter Edge ofProjection Film

As shown in Table 2, the films1and2are disposed near the inner glass plate in the thickness direction of the intermediate film. On the other hand, the film3is disposed near a central position in the thickness direction of the intermediate film. The results of the measurement of a double image are as shown below.

TABLE 3DistanceDistanceL1 (mm)L1 (mm)fromfromOuter EdgeOuter Edge(Upper Side) of(Right Side) ofDoubleBase Film toBase Film toImageProjection FilmProjection Film(minutes)Film 11812575 or more68125711812501187501182535Film 2211334071133412113321218331218315Film 381253010125121812516812501181250118750118250

The reference value of the double image is 25 minutes or less, and therefore, from the results regarding the above films1and2, it was found that, if the projection film133was disposed near the inner glass plate12, a double image larger than the reference value was not formed on the projection film133when the distance L1 was no less than 26.8 mm, as with the results shown inFIG.8. On the other hand, it was found that, if the projection film133was disposed near the central position in the thickness direction of the intermediate film13as in the case of the film3, a double image larger than the reference value was not formed on the projection film133when the distance L1 was no less than 10 mm.

By the way, in the above-described example inFIG.6, all sides of the functional layer13(the base film138) are disposed in the laminated glass10. However, as shown inFIG.9, it is possible to employ a configuration in which h the outer edge of a portion of the functional layer13reaches the end edge of the laminated glass10. In such a case, the outer edge of the portion of the functional layer13is exposed to the outside from a position between the outer glass plate11and the inner glass plate12. With such a configuration, a bulge is less likely to be caused by the above-described step, and a double image can be prevented from being formed on the projection film133. However, there is the risk of water entering from the exposed end edge of the functional layer13. In this regard, with the configuration shown inFIG.6, the outer edge of the functional layer13is protected by the adhesion layers131and132and is not exposed to the outside from a position between the glass plates11and12, and water ingress is prevented. Note that the shapes of the base film138and the projection film133are not particularly limited, and any shape other than a rectangular shape may be employed.

<6-2>

The configuration of the obstructing layer4is not particularly limited, and the obstructing layer4may be disposed along the peripheral edge portions of the glass plates as described above. Also, the obstructing layer4may be provided with an extension portion42for an on-board camera (an information acquisition device) as shown inFIG.10. This extension portion42is provided with an imaging window (opening)421for a camera, so that images of the outside of the vehicle can be captured. In addition, it is possible to use this extension portion42to make the bracket that supports the camera invisible from the outside of the vehicle. The obstructing layer4according to the present invention may be provided with such an extension portion, or formed in various shapes. In addition, the shape of the imaging window421is not particularly limited, and may be a shape with a closed peripheral edge as shown inFIG.9, or a shape in which a portion thereof being open from the end of the extension portion.

For the obstructing layer4, various materials may be employed in addition to the above-mentioned materials. For example, a material with an infrared transmittance of no greater than 5% may be employed. By using such a material, it is possible to achieve a heat shielding effect at the peripheral edge of the windshield. Further, when a heat shield film is used for the functional layer133, the heat shield film can be made smaller. That is to say, in the heat shield film, the area of the portion hidden by the obstructing layer4can be reduced.

In addition, in order to prevent the functional layer133from affecting imaging performed by the on-board camera, it is preferable that the functional layer133is formed so as not to overlap the imaging window421. For example, as shown inFIG.11, the a through hole134may be formed in a portion that overlaps the imaging window421of the functional layer133. This through hole134may be disposed inward of the outer edge of the extension portion42, and may have a shape that surrounds the imaging window421. In addition, a distance L2 between the through hole134and the imaging window421is preferably no less than 10 mm. This is because, as described above, a step is formed in the intermediate film13due to the outer edge of the functional layer133, and a double image is formed in a given range from the outer edge of the functional layer133in a planer direction. In this example, the step formed due to the presence of the inner edge of the through hole134in the functional layer133may generate a double image larger than the reference value, at a position inward of the inner edge (the above-mentioned double image on the X2 side). Therefore, it is preferable that the imaging window421is separated from the inner edge of the through hole134by at least 10 mm. In particular, when the distance between the functional layer133and the outer glass plate11or the inner glass plate12(the thickness of the first adhesion layer131or the second adhesion layer132) is no greater than 10 μm, it is preferable that the distance L2, calculated in the same manner as the above distance L1, is no less than 26.8 mm.

Also, instead of forming a through hole in the functional layer133as described above, a cutout135may be formed in the upper edge of the functional layer133as shown inFIG.12. The imaging window421may be formed upward of the cutout135. This cutout135may be located inward of the outer edge of the extension portion42, and may have a shape that passes through the periphery of the imaging window421. In addition, the distance L2 between the cutout135and the imaging window421may be set in the same manner as described above.

The above-described imaging window421may also be used for various sensors other than the on-board camera.

<6-3>

Although the above embodiment describes an example in which the automobile laminated glass according to the present invention is applied to a windshield, the automobile laminated glass may also be applied to a rear window, a side window, and so on.

EXAMPLES

The following describes examples of the present invention. Note that the present invention is not limited to the following embodiments.

Windshields according to Examples 1 to 15 and Comparative Examples 1 to 4 manufactured using the method described in the above embodiment were prepared. Dimensions and so on are as shown below. Note that the definitions of the dimensions shown below are the same as those shown in the above embodiment.

TABLE 4Vertical DirectionHorizontal DirectionAmountCurvedStraightCurvedStraightofLineLineBendingLineLineBendOPOPrvDepthQRQRrH(mm)(mm)(mm)(%)(mm)(mm)(mm)(%)Example 119.7902.35901.1699.8733.91346.161343.899.82Example 233.21058.041055.299.7337.61371.421368.5299.79Example 317.1897896.1199.9058.451418.05141199.50Example 424.11266.051264.6499.8975.481532.981520.8199.21Example 516.2828.89827.9399.8881.2915171503.8999.14Example 621.01021.931020.7199.8887.261522.011507.4299.04Example 715.8839.56838.7799.91148.241671.171630.897.58Example 825.41119.231117.4999.8442.61471.051467.599.76Example 915.4832.07831.2899.91101.081449.621429.198.58Example 1013.0931.71931.299.9580.71547.291535.9599.27Example 1121.851006.181005.2199.9092.411464.951451.599.08Example 1221.851006.181005.2199.9092.411464.951451.599.08Example 1321.851006.181005.2199.9092.411464.951451.599.08Example 1421.851006.181005.2199.9092.411464.951451.599.08Example 1521.851006.181005.2199.9092.411464.951451.599.08Comparative21.91006.521005.1899.8792.411466.771450.3798.88Example 1Comparative21.851006.181005.2199.9092.411464.951451.599.08Example 2Comparative22.6932.1930.5199.83128.661546.181513.9697.92Example 3Comparative22.9905.29903.699.81106.31337.661312.9598.15Example 4Comparative21.4904.94903.5399.84123.781498.931465.3797.76Example 5

All of the intermediate films (materials A to G) used for the windshields according to the above Examples 1 to 15 and Comparative Examples 1 to 4 are the same as described below, and are each constituted by two adhesion layers and a functional layer interposed therebetween.First Adhesion Layer: Polyvinyl butyral resin (PVB), thickness 380 μmSecond Adhesion Layer: Polyvinyl butyral resin (PVB), thickness 380 μmFunctional Layer: Three types of heat-reflecting films were used as functional layers. The heat shrinkage rMDand rTDof each functional layer in the MD direction and the TD direction are as shown in Table 3 below. The size of the outer edge of each functional layer was adjusted so as to be located at a position that is 10 mm inward of the outer edge of the glass plates. The thickness of each functional layer was 50 μm.

TABLE 5Material NamerMDrTDExample 1A99.4%99.4%Example 2A99.4%99.4%Example 3A99.4%99.4%Example 4A99.4%99.4%Example 5A99.4%99.4%Example 6A99.4%99.4%Example 7A99.4%99.4%Example 8A99.4%99.4%Example 9A99.4%99.4%Example 10A99.4%99.4%Example 11B99.0%98.7%Example 12D97.9%98.5%Example 13E98.9%96.6%Example 14F97.2%97.7%Example 15G99.5%99.6%ComparativeA99.4%99.4%Example 1ComparativeC100.0%99.8%Example 2ComparativeA99.4%99.4%Example 3ComparativeA99.4%99.4%Example 4

Regarding Examples 1 to 15 and Comparative Examples 1 to 4, the above-described Formulas (1) and (2) were examined, and the presence or absence of wrinkles on the peripheral edge portion of the functional layer was visually observed. The results are as shown below.

TABLE 6Formula (1)Formula (2)rV× rH≥rV≥rV≥rMD× rTD0.9990rTDWrinklesExample 1YESNOYESAbsentExample 2YESNOYESAbsentExample 3YESYESYESAbsentExample 4YESNOYESAbsentExample 5YESNOYESAbsentExample 6YESNOYESAbsentExample 7NOYESYESAbsentExample 8YESNOYESAbsentExample 9NOYESYESAbsentExample 10YESYESYESAbsentExample 11YESYESYESAbsentExample 12YESYESYESAbsentExample 13YESYESYESAbsentExample 14YESYESYESAbsentExample 15YESNOYESAbsentComparativeNONOYESPresentExample 1ComparativeNOYESNOPresentExample 2ComparativeNONOYESPresentExample 3ComparativeNONOYESPresentExample 4ComparativeNONOYESPresentExample 5

As shown in Table 6, Examples 1 to 11 satisfied at least one of Formulas (1) and (2), and as a result, wrinkles were not formed on the peripheral edge portion of the functional layer. In contrast, Comparative Examples 1 to 4 did not satisfy Formulas (1) or (2), and as a result, wrinkles were formed on the peripheral edge portion of the functional layer.

LIST OF REFERENCE NUMERALS

10Laminated Glass11Outer Glass Plate (First Glass Plate)12Inner Glass Plate (Second Glass Plate)13Intermediate Film131First Adhesion Layer132Second Adhesion Layer133Functional Layer4Obstructing Layer