JP2022183166A - windshield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a windshield which improves a degree of freedom in designing a shield layer.

SOLUTION: A windshield comprises: a glass pane including an information acquisition region which faces an information acquisition device and through which a light is passed; a shield layer for shielding a field of view from the outside of a vehicle; and an information acquisition region heating part including a pair of bus bar parts and multiple heating wires for heating the information acquisition region. The shield layer includes a belt-like region extending along an end side of the glass pane, the information acquisition region are disposed adjacently to the inside of the belt-like region in a surface direction, and both the bus bar parts of the information acquisition region heating part are arranged side by side so as to be included in the belt-like region in a visual field direction. The heating wires of the information acquisition region heating part are connected in parallel with both the bus bar parts, extend from one bus bar part to the inside in the surface direction, pass on the information acquisition region, are folded back and extend to the other bus bar part.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to windshields for motor vehicles.

For example, at low temperatures, the windshield of an automobile may fog or even freeze due to the temperature difference between the inside and outside of the vehicle, which may interfere with driving. To address this, various methods have been proposed to remove fog or ice from windshields. For example, Patent Literature 1 proposes disposing a bus bar and a heating wire inside the windshield to generate heat to remove fogging.

Further, in recent years, an in-vehicle system has been proposed in which a camera is installed inside the vehicle to photograph the situation outside the vehicle. This in-vehicle system recognizes oncoming vehicles, vehicles in front, pedestrians, traffic signs, lane boundaries, etc. by analyzing the images of the subject acquired by the camera. Driving assistance can be provided.

However, in general, a shielding layer is provided along the periphery of the windshield to block the field of view from outside the vehicle. It is installed at a position where the shielding layer can be included in the photographing range of the camera. Therefore, there is a possibility that the shielding layer will interfere with the imaging of the camera.

Therefore, Patent Documents 2 and 3 propose to provide a transmission window in a part of the shielding layer. For example, by replacing part of the interlayer with a material with high visible light transmittance, or by providing an area where ceramics are not laminated, a part of the shielding layer with high visible light transmittance (transmission window ) can be formed. This allows the camera installed inside the vehicle to photograph the situation outside the vehicle without being obstructed by the shielding layer.

JP-A-2000-077173 JP 2006-327381 A Japanese Patent Application Laid-Open No. 2007-039278

Since the transmissive window is also part of the windshield, it can fog up or freeze, along with other areas. Therefore, it is conceivable to arrange heating wires as described above also in the transmissive window to remove fogging and/or ice. However, the inventors of the present invention have found that the following problems arise when the busbars and heating wires are arranged in the conventional manner.

Problems discovered by the inventors of the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 schematically illustrates a windshield 100 according to a conventional example. Moreover, FIG. 2 schematically illustrates the configuration of the busbar portion 104 and the heating wire 105 according to the conventional example. As illustrated in FIG. 1, a conventional windshield 100 is provided with a shielding layer 101 along the periphery.

In some cases, the shielding layer 101 is provided with a protruding region 102 that protrudes inward in the surface direction from a portion along the upper edge of the windshield 100, and a camera is arranged inside the vehicle so as to be hidden in the protruding region 102. In this case, the transmissive window 103 as described above is provided in the projected area 102 so that the camera can photograph the situation outside the vehicle.

At this time, assuming that a heating unit for heating the transmissive window 103 is configured as in the conventional example illustrated in Patent Document 1, the bus bar unit 104 and the heating unit 105 that configure the heating unit are as illustrated in FIG. placed in That is, a pair of busbar portions 104 are arranged on both sides of the transmissive window 103, and a plurality of heating wires 105 are arranged so as to pass through the transmissive window 103 and be connected to both busbar portions 104 in parallel.

However, when the busbar portion 104 and the heating wire 105 are arranged in this way, in order to make the busbar portion 104 invisible from the outside of the vehicle, shielding layers (protruding regions 102 in the figure) are provided at least on both sides of the transmissive window 103. There must be. As a result, the inventors of the present invention have found that the shape of the shielding layer is partially fixed, and the degree of freedom in designing the shielding layer is narrowed.

SUMMARY OF THE INVENTION In one aspect, the present invention has been made in view of such circumstances, and an object thereof is to provide a windshield with a high degree of freedom in designing the shielding layer.

The present invention adopts the following configurations in order to solve the above-described problems.

That is, a windshield according to one aspect of the present invention is a windshield of an automobile on which an information acquisition device for acquiring information from outside the vehicle by irradiating and/or receiving light can be arranged, wherein the information acquisition device and a glass plate having an information acquisition area through which the light passes, a shielding layer provided on the glass plate for shielding a field of view from outside the vehicle, a pair of busbar portions and a plurality of heating wires, the information and an information acquisition area heating unit that heats the acquisition area. The shielding layer includes a band-shaped region extending along the edge of the glass plate, and the information acquisition region is arranged adjacent to the inner side of the band-shaped region in the plane direction, and is located on both sides of the information acquisition region heating unit. The busbar portions are arranged side by side so as to be included in the band-shaped region in the viewing direction. It extends inward, passes over the information acquisition area, and is folded back to extend toward the other busbar portion.

In the windshield according to this configuration, the information acquisition area for the information acquisition device to acquire information outside the vehicle is arranged adjacent to the strip-shaped area of the shielding layer in the plane direction, and the information acquisition area heats the information acquisition area. Both busbar portions forming the heating portion are arranged side by side in the belt-like region. As a result, both busbar portions are hidden in the belt-shaped area, so that it is not necessary to provide a shielding layer around the information acquisition area except for the outside of the information acquisition area in the plane direction. Therefore, according to this configuration, the shielding layer may or may not be provided in the area around the information acquisition area, so that the degree of freedom in designing the shielding layer can be increased.

Further, as another form of the windshield according to the above configuration, among the plurality of heating wires, the heating wire extending more inward in the surface direction may have a larger cross-sectional area. With the same cross-sectional area, the longer the length of the heating wire, the smaller the amount of heat generated by the heating wire according to the relational expression of Equation 1, which will be described later. Therefore, if all the heating wires have the same cross-sectional area, the amount of heat generated by the heating wires extending further outward in the plane direction is reduced, and there is a possibility that the entire information acquisition area cannot be heated evenly. This can result in partial fogging and/or ice remaining in the information acquisition area, or slow removal of fogging and/or ice. On the other hand, according to this configuration, by increasing the cross-sectional area of the heating wire extending more inward in the surface direction, the difference in the amount of heat generated between the heating wire extending more inward in the surface direction and the heating wire that does not. can be reduced. Therefore, according to this configuration, the information acquisition area can be evenly warmed, thereby appropriately removing fogging and/or ice from the information acquisition area. When the thickness of each heating wire is substantially constant, the cross-sectional area of each heating wire is proportional to the width of each heating wire (which may be referred to as "wire diameter"). Therefore, in this case, by adjusting the line width of each heating wire, the size of the cross-sectional area of each heating wire can be easily changed.

Further, as another form of the windshield according to the above configuration, at least one adjacent heating wire among the plurality of heating wires may have a portion extending parallel to each other, and the heating wires adjacent to each other may The parallel extending portions may each be wavy. When adjacent heating wires have portions extending parallel to each other, and the parallel extending portions of the heating wires adjacent to each other are formed in a straight line, light is diffracted in one direction due to diffraction of light occurring at the edges of these portions. reinforcement occurs. As a result, a linear pattern with high light intensity is generated, which may adversely affect the acquisition of information by the information acquisition device. On the other hand, by forming the parallel portions of the heating wires adjacent to each other in a wavy shape, the directions in which the light is strengthened can be dispersed in multiple directions, and the light intensity of the pattern generated in each direction is weakened. be able to. Therefore, according to this configuration, it is possible to prevent diffraction of light, which adversely affects acquisition of information by the information acquisition device, from occurring in the plurality of heating wires.

Further, as another form of the windshield according to the above configuration, the wavy patterns of the portions of the adjacent heating wires extending in parallel may be shifted from each other. According to this configuration, the directions in which light is strengthened can be dispersed in other directions, and the light intensity of the pattern generated in each direction can be weakened. Therefore, according to this configuration, it is possible to make it more difficult for the plurality of heating wires to cause diffraction of light that adversely affects acquisition of information by the information acquisition device.

Moreover, as another form of the windshield according to the above configuration, an anti-fogging film may be attached to the information acquisition area. According to this configuration, it is possible to make the information acquisition area less likely to fog up.

Moreover, as another form of the windshield according to the above configuration, the plurality of heating wires may be made of copper. Copper is a material that is easy to process. Also, since copper is chemically stable, it can be processed using chemical processing methods. Furthermore, copper is an inexpensive material compared to silver and the like. Therefore, the manufacturing cost can be suppressed by using copper for each heating wire. Furthermore, by making the bus bar portion also of copper, it is possible to prevent abnormal heat generation due to contact resistance that occurs when an electric current is applied across dissimilar materials.

Further, as another form of the windshield according to the above configuration, the windshield may further include a non-region heating unit that has one or more heating wires and heats a region other than the information acquisition region. According to this configuration, fogging and/or ice can be removed from areas other than the information acquisition area.

Further, as another form of the windshield according to the above configuration, the amount of heat generated per unit area of the information acquisition area heating section and the amount of heat generated per unit area of the other area heating section may be different. The reason for warming may be different between the information acquisition area and other areas. For example, the information acquisition area is heated to remove fogging, and the other areas are heated to remove (melt) ice. In such a case, the information acquisition area and other areas may not be heated with the same amount of heat. According to this configuration, by setting the heat generation amount per unit area of the information acquisition area heating section and the heat generation amount per unit area of the other area heating section so as to be different from each other, such a request can be met. can.

This can be easily achieved by adjusting the cross-sectional area of each heating wire. For example, the cross-sectional area of each heating wire of the information acquisition area heating section may be larger than that of the heating wire of the other area heating section. Thereby, the amount of heat generated per unit area of the information acquisition area heating section can be made larger than that of the other area heating section. On the other hand, the cross-sectional area of each heating wire of the information acquisition region heating section may be smaller than that of the heating wire of the other region heating section. As a result, the amount of heat generated per unit area of the information acquisition area heating section can be made smaller than that of the other area heating section.

According to the present invention, it is possible to provide a windshield with a high degree of freedom in designing the shielding layer.

FIG. 1 schematically illustrates a conventional windshield. FIG. 2 schematically illustrates the configuration of a conventional heating unit. FIG. 3 is a front view schematically illustrating the windshield according to the embodiment. FIG. 4 is a cross-sectional view schematically illustrating the windshield according to the embodiment. FIG. 5 schematically illustrates a cross section taken along line AA of FIG. FIG. 6 schematically illustrates a cross section taken along line BB of FIG. FIG. 7 schematically illustrates a manufacturing process of laminated glass according to the embodiment. FIG. 8 is a partially enlarged view schematically illustrating an information acquisition area heating portion of the windshield according to the embodiment. FIG. 9 shows an example in which straight wires are arranged in parallel. FIG. 10 shows the pattern produced when light is passed through straight wires arranged in parallel. FIG. 11 shows an example in which wavy (sinusoidal) wires are arranged in parallel. FIG. 12 shows the pattern produced when light is passed through wavy wires arranged in parallel. FIG. 13 schematically illustrates an information acquisition area heating section according to another embodiment. FIG. 14 schematically illustrates an information acquisition area heating section according to another embodiment. FIG. 15 is a cross-sectional view schematically showing an example of a transfer sheet. FIG. 16A schematically illustrates the process of transferring each heating portion to laminated glass using a transfer sheet. FIG. 16B schematically illustrates the process of transferring each heating portion to laminated glass using a transfer sheet. FIG. 16C schematically illustrates the process of transferring each heating portion to laminated glass using a transfer sheet. FIG. 17 schematically illustrates a windshield according to another embodiment. FIG. 18 illustrates a state in which water droplets are attached to the antifogging film. FIG. 19 illustrates a state in which water droplets are attached to the antifogging film. FIG. 20 schematically illustrates a windshield according to another form. FIG. 21 schematically illustrates an information acquisition area heating section according to another embodiment.

Hereinafter, an embodiment (hereinafter also referred to as "this embodiment") according to one aspect of the present invention will be described based on the drawings. However, this embodiment described below is merely an example of the present invention in every respect. It goes without saying that various modifications and variations can be made without departing from the scope of the invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be appropriately employed. In addition, in the following description, for convenience of description, the directions in the drawings are used as a reference.

§1 Configuration Example First, the windshield 1 according to the present embodiment will be described with reference to FIGS. 3 to 6. FIG. 3 and 4 are a front view and a sectional view schematically illustrating the windshield 1 according to this embodiment. 5 and 6 schematically illustrate cross sections taken along line AA and line BB of FIG. 3, respectively.

As shown in each figure, the windshield 1 according to the present embodiment includes a laminated glass 2 in which an outer glass plate 21 arranged on the outside of the vehicle and an inner glass plate 22 arranged on the inner side of the vehicle are joined by an intermediate layer 4. I have. This laminated glass 2 corresponds to the "glass plate" of the present invention. A shielding layer 3 is provided along the periphery of the laminated glass 2 to shield the view from outside the vehicle.

In this embodiment, as exemplified in FIGS. 3 and 4 , the shielding layer 3 has a band-like shape extending along the upper edge of the laminated glass 2 substantially in the center of the portion along the upper edge of the laminated glass 2 . A region 31 is set. In addition, a bracket (not shown) is installed in the interior of the automobile to which the laminated glass 2 is attached so that the area where the shielding layer 3 is not provided inside (that is, below) the band-shaped area 31 in the plane direction is included in the angle of view. A photographing device 8 is attached via, for example. As a result, the information acquisition area 23 facing the imaging device 8 and through which light passes is set to be adjacent to the inner side of the band-shaped area 31 in the plane direction. That is, the busbar portion 51 is arranged in the band-shaped region 31 and the information acquisition region 23 is arranged inside the busbar portion 51 in the plane direction. This photographing device 8 corresponds to the "information acquisition device" of the present invention.

Further, in the present embodiment, an information acquisition area heating unit 5 that heats the information acquisition area 23 and another area heating unit 6 that heats an area other than the information acquisition area 23 are provided in the intermediate layer 4 . The inner glass plate 22 is provided with cutouts 223 to 226 so that terminals can be connected to the heating portions (5, 6). As a result, fogging and/or ice on the information acquisition area 23 and other areas can be removed. Each component will be described below.

[Outer glass plate and inner glass plate]
First, the outer glass plate 21 and the inner glass plate 22 will be described. The outside glass plate 21 has a first surface 211 on the outside of the vehicle and a second surface 212 on the inside of the vehicle. Similarly, the inner glass plate 22 has a third surface 221 on the outside of the vehicle and a fourth surface 222 on the inside of the vehicle.

The two glass plates (21, 22) have substantially the same shape and are trapezoidal in plan view. Both glass plates (21, 22) may be curved in the perpendicular direction or may be flat. For example, both glass plates (21, 22) may have a curved shape such that the first surface 211 and the third surface 221 are convex and the second surface 212 and the fourth surface 222 are concave.

A well-known glass plate can be used for each glass plate (21, 22). For example, each glass plate (21, 22) may be heat-absorbing glass, clear glass, green glass, UV green glass, or the like. However, each glass plate (21, 22) is configured to achieve a visible light transmittance that meets the safety standards of the country in which the automobile is used. For example, each glass plate (21, 22) may be configured to have a transmittance of 70% or more for visible light (380 nm to 780 nm) as defined by JIS R 3211. The transmittance can be measured by the spectrometry method specified in JIS Z 8722 as specified in JIS R 3212 (3.11 Visible light transmittance test). Alternatively, for example, the outer glass plate 21 can ensure a desired solar absorptivity, and the inner glass plate 22 can be adjusted so that the visible light transmittance satisfies safety standards. An example of the composition of the clear glass and an example of the composition of the heat-absorbing glass are shown below as examples of the composition of the glass that can constitute the glass plates (21, 22).

(clear glass)
SiO ₂ : 70-73% by mass
Al ₂ O ₃ : 0.6 to 2.4% by mass
CaO: 7 to 12% by mass
MgO: 1.0 to 4.5% by mass
R ₂ O: 13-15% by mass (R is an alkali metal)
Total iron oxide (T-Fe ₂ O ₃ ) converted to Fe ₂ O ₃ : 0.08 to 0.14% by mass

(heat-absorbing glass)
The composition of the heat-absorbing glass is, for example, based on the composition of the clear glass, the ratio of total iron oxide (T-Fe ₂ O ₃ ) converted to Fe ₂ O ₃ is 0.4 to 1.3% by mass, and CeO ₂ is 0 to 2% by mass, the ratio of TiO ₂ is 0 to 0.5% by mass, and the framework components of the glass (mainly SiO ₂ and Al ₂ O ₃ ) are T—Fe ₂ O ₃ and CeO. ₂ and TiO ₂ increments.

The thickness of the laminated glass 2 according to the present embodiment is not particularly limited, but from the viewpoint of weight reduction, the total thickness of both glass plates (21, 22) is preferably 2.5 mm to 10.6 mm. It is more preferably 2.6 mm to 3.8 mm, particularly preferably 2.7 mm to 3.2 mm. Thus, for weight reduction, the total thickness of both glass plates (21, 22) should be reduced. Although the thickness of each glass plate (21, 22) is not particularly limited, for example, the thickness of each glass plate (21, 22) can be determined as follows.

That is, the outer glass plate 21 is mainly required to have durability and impact resistance against impacts such as flying objects such as pebbles. On the other hand, it is not preferable to increase the thickness of the outer glass plate 21 because the weight increases. From this point of view, the thickness of the outer glass plate 21 is preferably 1.6 mm to 2.5 mm, more preferably 1.9 mm to 2.1 mm. Which thickness to adopt can be appropriately determined according to the embodiment.

On the other hand, the thickness of the inner glass plate 22 can be made equal to the thickness of the outer glass plate 21, but for example, in order to reduce the weight of the laminated glass 2, the thickness can be made smaller than that of the outer glass plate 21. . Specifically, considering the strength of the glass, the thickness of the inner glass plate 22 is preferably 0.6 mm to 2.1 mm, more preferably 0.8 mm to 1.6 mm, and more preferably 1.0 mm. ~1.4 mm is particularly preferred. Furthermore, the thickness of the inner glass plate 22 is preferably 0.8 mm to 1.3 mm. Regarding the inner glass plate 22 as well, which thickness to adopt can be appropriately determined according to the embodiment.

[Shielding layer]
Next, the shielding layer 3 that shields the field of view from outside the vehicle will be described. In this embodiment, the shielding layer 3 is provided on the fourth surface 222 of the inner glass plate 22, as shown in FIGS. 4-6. The shielding layer 3 is laminated along the peripheral edge of the fourth surface 222 of the inner glass plate 22 and shields the incident light from the peripheral edge of the laminated glass 2 .

On the other hand, light can pass through the area where the shielding layer 3 is not provided, and the driver and the companion sitting in the front passenger seat of the car equipped with the windshield 1 can see this area. You will be able to check the front outside the vehicle through. Therefore, the area where the shielding layer 3 is not provided is configured to have visible light transmittance at least to the extent that the traffic conditions outside the vehicle can be visually observed.

In this embodiment, a band-shaped region 31 is provided substantially in the center of the portion along the upper edge of the laminated glass 2 , and the information acquisition region 23 is provided below and adjacent to the band-shaped region 31 . As shown in FIG. 4 , the photographing device 8 arranged inside the vehicle from the laminated glass 2 photographs the situation outside the vehicle via the information acquisition area 23 . Therefore, the information acquisition area 23 may be configured to have a visible light transmittance of 70% or more as defined by JIS R 3211, for example, as described above.

Note that the dimensions of each part of the shielding layer 3 may be appropriately set according to the embodiment. For example, the width of the portions along the upper edge and lower edge of the laminated glass 2 may be set within the range of 20 mm to 100 mm. Also, the width of the portions along the left edge and right edge of the laminated glass 2 may be set within a range of 15 mm to 70 mm.

Also, the material of the shielding layer 3 may be appropriately selected according to the embodiment. For example, the shielding layer 3 can be made of dark-colored ceramic such as black, brown, gray, and navy blue. Specifically, the shielding layer 3 can be formed from a ceramic having the composition shown in Table 1 below. However, the composition of the ceramic forming the shielding layer 3 is not limited to Table 1 below, and may be appropriately selected according to the embodiment.

＊１，アサヒ化成工業株式会社製：Black 6350（Pigment Green 17）
＊２，主成分：ホウケイ酸ビスマス、ホウケイ酸亜鉛

*1, Asahi Chemical Industry Co., Ltd.: Black 6350 (Pigment Green 17)
*2, Main components: bismuth borosilicate, zinc borosilicate

Also, the band-shaped region 31 can be set within a range of 10 mm to 50 mm in width from the upper edge of the laminated glass 2 . Furthermore, in the example of FIG. 3, the shape of the lower end side of the band-shaped area 31 is linear. However, the shape of the lower end side of the band-shaped region 31 does not have to be limited to such an example. For example, the lower end of the band-shaped region 31 may be curved or uneven with a width of 10 mm to 50 mm.

Furthermore, in FIG. 3, the band-shaped area 31 and the information acquisition area 23 are slightly separated. "The information acquisition area is arranged adjacent to the inside of the band-like area in the plane direction" does not mean that the information acquisition area and the band-like area are connected, and may include such a state that the information acquisition area and the band-like area are slightly separated.

[Middle layer]
Next, the intermediate layer 4 will be explained. In this embodiment, the intermediate layer 4 has a three-layer structure. That is, the intermediate layer 4 includes a heat generating layer including the information acquisition area heating section 5 and the other area heating section 6, and a pair of adhesive layers (42, 43) sandwiching the heat generating layer. Each layer will be described below.

<Heat generation layer>
First, the heating layer will be explained. The heat generation layer includes a sheet-like base material 41 and the information acquisition area heating section 5 and the other area heating section 6 arranged on the base material 41 . The shape of the substrate 41 may be the same as the glass plates (21, 22), or may be smaller than the glass plates (21, 22).

(Information acquisition area heating unit)
The information acquisition area heating unit 5 is configured to heat the information acquisition area 23 set in the laminated glass 2 to remove fogging and/or ice from the information acquisition area 23 . Specifically, as illustrated in FIGS. 3 to 5, the information acquisition area heating section 5 includes a pair of busbar sections 51 arranged on the base material 41 and connected to both busbar sections 51 in parallel. It has three heating wires 52A-52C. In addition, below, these are also called 52 A of 1st heating wires, 52 B of 2nd heating wires, and 52 C of 3rd heating wires for convenience of explanation.

As shown in each figure, both busbar portions 51 are arranged so as to be included in the belt-like region 31 of the shielding layer 3 in the viewing direction. The visual field direction is the visual field direction of the driver and the companions sitting in the front passenger seat when the windshield 1 is attached to the automobile. ) in the perpendicular direction). In addition, as shown in FIG. 3 , both busbar portions 51 are arranged side by side in the direction in which strip-shaped region 31 extends, that is, in the left-right direction. Further, both busbar portions 51 are arranged inward in the plane direction from the cutouts (223, 224) formed in the upper edge of the inner glass plate 22 so as not to be exposed from the cutouts (223, 224). there is Each of the heating wires 52A to 52C extends from one busbar portion 51 inward (that is, downward) in the plane direction, passes over the information acquisition area 23, and is folded back to connect to the other busbar portion 51. As shown in FIG.

In this embodiment, each of the heating wires 52A to 52C is formed in a substantially U-shape as an example of its shape. That is, each of the heating wires 52A to 52C has a pair of lateral side portions facing each other in the horizontal direction and extending in the vertical direction, and a lower end portion extending in the lateral direction so as to connect the lower ends of the both side portions. .

The second heating wire 52B is arranged outside the third heating wire 52C and extends from each busbar portion 51 to the inside in the plane direction. Therefore, the second heating wire 52B is longer than the third heating wire 52C. Similarly, the first heating wire 52A is arranged outside the second heating wire 52B and extends inward in the plane direction from each busbar portion 51 . Therefore, the first heating wire 52A is longer than the second heating wire 52B.

The line width of each heating line 52A to 52C can be, for example, 1 μm to 500 μm, preferably 5 μm to 100 μm, more preferably 5 μm to 15 μm. Correspondingly, the cross-sectional area of each heating wire 52A-52C can be, for example, 1 μm ² to 250000 μm ² , preferably 25 μm ² to 10000 μm ² , more preferably 25 μm ² to 225 μm ² . is more preferred. The cross-sectional area of each of the heating wires 52A to 52C can be measured, for example, by observing the cross section magnified 150 times using a microscope. It should be noted that the heating wires 52A to 52C may have different cross-sectional areas. In this case, the cross-sectional area measurement point may be set at the central portion of each of the heating wires 52A to 52C. Also, the cross-sectional areas of the heating wires 52A to 52C may be the same. However, the following equations 1 to 3 are known for the amount of heat generated by the heating wires 52A to 52C.

なお、Ｖは電圧（電位差）、Ｉは電流、Ｒは抵抗、ρは電気抵抗率、Ｌは導体の長さ、Ａは導体の断面積、Ｗは発熱量（消費電力）を示す。ここで、一般的には、自動車の電圧は一定であるため、上記数１～数３に示されるＶの値は一定であるとしてよい。同様に、電気抵抗率ρは材料によって定まるため、各加熱線５２Ａ～５２Ｃの材料が同じであるとの前提のもと、上記数１～数３に示されるρの値も一定であるとしてよい。また、各加熱線５２Ａ～５２Ｃの断面の形状が矩形状であるとすると、各加熱線５２Ａ～５２Ｃの断面積は、厚みと線幅との積により求めることができる。加えて、各加熱線５２Ａ～５２Ｃの厚みがほぼ一定であるとすると、各加熱線５２Ａ～５２Ｃの断面積は線幅に比例する。そのため、厚みがほぼ一定である場合には、各加熱線５２Ａ～５２Ｃの線幅を調節することで、各加熱線５２Ａ～５２Ｃの断面積を容易に変更することができる。つまり、各加熱線５２Ａ～５２Ｃの線幅を小さくすることで各加熱線５２Ａ～５２Ｃの断面積を小さくすることができ、各加熱線５２Ａ～５２Ｃの線幅を大きくすることで各加熱線５２Ａ～５２Ｃの断面積を大きくすることができる。したがって、各加熱線５２Ａ～５２Ｃの厚みがほぼ一定である場合には、各加熱線５２Ａ～５２Ｃの断面積はその線幅に比例するとして、各加熱線５２Ａ～５２Ｃの断面積をその線幅を調節することで変更してもよい。ただし、各加熱線５２Ａ～５２Ｃの断面の形状は、矩形状に限定される訳ではなく、台形状、多角形、円形状等であってもよい。

Here, V is voltage (potential difference), I is current, R is resistance, ρ is electrical resistivity, L is conductor length, A is cross-sectional area of conductor, and W is calorific value (power consumption). Here, since the voltage of a vehicle is generally constant, the value of V shown in Equations 1 to 3 may be assumed to be constant. Similarly, since the electrical resistivity ρ is determined by the material, on the premise that the materials of the heating wires 52A to 52C are the same, the values of ρ shown in Equations 1 to 3 above may also be constant. . Also, if the cross-sectional shape of each of the heating wires 52A to 52C is rectangular, the cross-sectional area of each of the heating wires 52A to 52C can be obtained by multiplying the thickness by the line width. In addition, assuming that the thickness of each heating wire 52A-52C is substantially constant, the cross-sectional area of each heating wire 52A-52C is proportional to the wire width. Therefore, when the thickness is substantially constant, the cross-sectional area of each heating wire 52A-52C can be easily changed by adjusting the line width of each heating wire 52A-52C. That is, by reducing the line width of each heating wire 52A to 52C, the cross-sectional area of each heating wire 52A to 52C can be reduced, and by increasing the line width of each heating wire 52A to 52C, each heating wire 52A The cross-sectional area of ~52C can be increased. Therefore, when the thickness of each heating wire 52A-52C is substantially constant, the cross-sectional area of each heating wire 52A-52C is assumed to be proportional to its wire width. can be changed by adjusting the However, the cross-sectional shape of each of the heating wires 52A to 52C is not limited to a rectangular shape, and may be trapezoidal, polygonal, circular, or the like.

From Equations 1 to 3 above, when the cross-sectional area is the same, the longer the length of the heating wire, the smaller the heating value (W) of the heating wire. Therefore, if the heating wires 52A to 52C have the same cross-sectional area, the heating wire that extends further inward in the surface direction from both busbar portions 51 will generate less heat.

That is, the amount of heat generated by the second heating wire 52B becomes smaller than that of the third heating wire 52C, and the amount of heat generated by the first heating wire 52A becomes smaller than that of the second heating wire 52B. As a result, there is a possibility that the entire information acquisition area 23 cannot be warmed evenly. In particular, in the information acquisition area 23, the amount of heat generated becomes small in a portion away from both busbar portions 51, and there is a possibility that removal of fog and/or ice will be delayed in this portion.

Therefore, in this embodiment, the heating wires 52A to 52C may have different cross-sectional areas. Specifically, the cross-sectional area of the heating wire may be increased as the heating wire extends further inward in the surface direction from both busbar portions 51 . That is, the cross-sectional area of the second heating wire 52B may be made larger than that of the third heating wire 52C, and the cross-sectional area of the first heating wire 52A may be made larger than that of the second heating wire 52B. Thereby, the difference in the amount of heat generated by the heating wires 52A to 52C can be suppressed, and the information acquisition area 23 can be evenly heated.

However, depending on the arrangement and shape of the heating wires 52A to 52C, even if the cross-sectional areas of the heating wires 52A to 52C are adjusted, the entire information acquisition area 23 may not be evenly heated. Therefore, it is preferable to appropriately adjust the shape (particularly, the arrangement within the information acquisition area 23), length, and cross-sectional area of each of the heating wires 52A to 52C so that the entire information acquisition area 23 can be evenly heated. preferable.

The dimensions of each busbar portion 51, the interval between both busbar portions 51, and the interval between the heating wires 52A to 52C may be appropriately set according to the embodiment. However, when both the busbar portions 51 and the heating wires 52A to 52C have substantially the same thickness, if the width of each busbar portion 51 is less than 10 times the width of the heating wires 52A to 52C (for example, each When the width of each of the heating wires 52A to 52C is 500 μm, if the width of each busbar portion 51 is less than 5 mm, each busbar portion 51 itself may generate abnormal heat. As a result, there is a possibility that the heat generation efficiency of the information acquisition area heating section 5 will decrease. Also, if the size of each busbar portion 51 is too small, it may be difficult to connect the connection terminal (anode terminal or cathode terminal: not shown) provided on each busbar portion 51 . On the other hand, if the size of each busbar portion 51 is too large, each busbar portion 51 may protrude from the shielding layer 3 and obstruct the field of vision. From these points of view, the dimensions of each busbar portion 51 may be set to, for example, 5 mm (horizontal)×5 mm (vertical) to 60 mm (horizontal)×60 mm (vertical). Also, the distance between the busbar portions 51, that is, the distance between the horizontal centers of the busbar portions 51 may be 10 mm to 120 mm. Further, for example, the distance between the portions of the heating wires 52A to 52C extending in the horizontal direction may be 1 mm to 50 mm, preferably 10 mm to 50 mm, in the vertical direction. Furthermore, for example, the distance between the vertically extending portions of the heating wires 52A to 52C may be 5 mm to 40 mm, preferably 10 mm to 40 mm, in the horizontal direction.

In addition, in this embodiment, as shown in FIGS. 3 and 5, a connection member 71 is used to energize the busbar portions 51 and the heating wires 52A to 52C. That is, the connection member 71 is for connecting each bus bar portion 51 and a connection terminal (anode terminal or cathode terminal: not shown), and is formed in a sheet shape from a conductive material, for example.

As shown in FIG. 5 , each connecting member 71 is formed in a rectangular shape and sandwiched between each busbar portion 51 and the adhesive layer 43 . Each connection member 71 is fixed to each busbar portion 51 by a fixing member 72 such as solder. Solder having a low melting point of 150° C. or less, for example, is preferably used for the fixing member 72 so that the fixing member 72 can be simultaneously fixed in an autoclave when assembling the windshield, which will be described later.

Each connecting member 71 extends from each busbar portion 51 to the upper edge of the outer glass plate 21 and is exposed from each notch (223, 224) formed in the upper edge of the inner glass plate 22. . At this exposed portion, the connecting terminals of the cables extending from the power source of the automobile are connected by a fixing material such as solder, so that electricity is supplied from the power source to the heating wires 52A to 52C through the busbar portions 51 to heat them. be able to

In this way, each connection member 71 does not protrude from the ends of both glass plates (21, 22), and fixes the connection terminal to the portion exposed from each notch (223, 224) of the inner glass plate 22. It is possible to do so. Each connection member 71 may be made of a thin material, in which case it can be bent and then fixed to each busbar portion 51 with a fixing member 72 at its end.

(other area heating unit)
On the other hand, the other area heating unit 6 heats the area other than the information acquisition area 23 of the laminated glass 2, particularly the visual field area (area within the visual field) of the driver and the companion sitting in the passenger seat, and heats the information acquisition area 23. It is a configuration to remove fogging and/or ice in this area other than. Specifically, as illustrated in FIGS. 3 to 6, the other area heating unit 6 includes a pair of busbar portions 61 arranged on the base material 41 and extending in the left-right direction. It has a plurality of heating wires 62 connected in parallel. In addition, in FIG. 3, the number of the heating wires 62 is six. However, the number of heating wires 62 need not be limited to such an example, and may be appropriately selected according to the embodiment. The number of heating wires 62 may be 1 to 5, or may be 7 or more.

As shown in FIG. 3, each busbar portion 61 is formed to extend along each of the left and right edges. Each busbar portion 61 is arranged inward in the plane direction from each cutout (225, 226) so as not to be exposed from the cutout (225, 226) formed in each of the left and right edges of the inner glass plate 22. there is In addition, each busbar portion 61 is arranged so as to be included in portions along the left and right edges of the shielding layer 3 in the viewing direction.

The dimensions of each busbar portion 61 may be appropriately set according to the embodiment. However, when each busbar portion 61 and the heating wire 62 have the same thickness, if the width of each busbar portion 61 is smaller than ten times the wire width of the heating wire 62 (for example, the wire width of the heating wire 62 is If the width of each busbar portion 61 is less than 5 mm when the width is 500 μm, each busbar portion 61 itself may generate abnormal heat. As a result, there is a possibility that the heat generation efficiency of the other area heating unit 6 will decrease. On the other hand, if the width of each busbar portion 61 is greater than 50 mm, each busbar portion 61 may protrude from the shielding layer 3 and obstruct the field of view. Therefore, it is preferable that the width of each busbar portion 61 is, for example, 5 mm to 50 mm. In order to suppress the heat generation of each busbar portion 61 itself, it is preferable that the width of each busbar portion 61 is less than ten times the line width of the heating wire 62 . Note that each busbar portion 61 does not have to be formed along the base material 41 precisely. That is, each busbar portion 61 may not be completely parallel to the edge of the base material 41, and may be formed in a curved shape or the like.

Each heating wire 62 extends linearly in the left-right direction and is connected to both busbar portions 61 . Each heating wire 62 is arranged substantially parallel to the vertical direction. The line width and spacing of each heating wire 62 may be appropriately set according to the embodiment. For example, a driver and a companion sitting in the front passenger's seat of a vehicle equipped with the windshield 1 check the conditions outside the vehicle through the areas provided with the heating wires 62 . From this point of view, the line width of each heating wire 62 is preferably 3 μm to 20 μm, more preferably 5 μm to 13 μm, and particularly preferably 8 μm to 10 μm. The interval between adjacent heating wires 62 can be 1 mm to 100 mm, preferably 1 mm to 50 mm, and more preferably 1 mm to 10 mm.

The amount of heat generated per unit area of the information acquisition area heating section 5 and the amount of heat generated per unit area of the other area heating section 6 may be different. The other area heating unit 6 heats the visual field areas of the driver and the companion sitting in the front passenger seat, while the information acquisition area heating unit 5 heats the area (information acquisition area) within the angle of view of the imaging device 8. . Therefore, the heating range of each heating unit (5, 6) is greatly different, and the purpose of heating may also be different. Therefore, it is not necessary to heat the information acquisition area 23 and other areas with the same amount of heat.

For example, the information acquisition area 23 is heated to remove fogging, and other areas are heated to remove ice. In such a case, it is preferable to set the heating amount per unit area of the other area heating section 6 to be larger than that of the information acquisition area heating section 5 . Thus, the amount of heat generated per unit area of the information acquisition area heating section 5 and the amount of heat generated per unit area of the other area heating section 6 may be different.

Here, as shown in the above-described equations 1 to 3, by changing the cross-sectional area of each heating wire (52A to 52C, 62), the heat generation amount of each heating wire (52A to 52C, 62) can be easily adjusted. For example, the cross-sectional areas of the heating wires 52A to 52C of the information acquisition region heating section 5 may be larger than the heating wires 62 of the other region heating section 6. FIG. Thereby, the amount of heat generated per unit area of the information acquisition area heating section 5 can be made larger than that of the other area heating section 6 . On the other hand, the cross-sectional areas of the heating wires 52A to 52C of the information acquisition region heating section 5 may be smaller than the heating wires 62 of the other region heating section 6. FIG. As a result, the amount of heat generated per unit area of the information acquisition area heating section 5 can be made smaller than that of the other area heating section 6 . The adjustment of the cross-sectional area of each heating wire (52A to 52C, 62) may be achieved by changing the line width of each heating wire (52A to 52C, 62) as described above. .

Further, in the present embodiment, as shown in FIGS. 3 and 6, in the same way as the information acquisition area heating unit 5, since the busbar portions 61 and the heating wires 62 are energized, the connecting members 73 and the fixing members 74 are is used. The connecting member 73 corresponds to the connecting member 71 , and the fixing member 74 for fixing the connecting member 71 to each busbar portion 61 corresponds to the fixing member 72 .

That is, each connection member 73 is connected to each busbar portion 61 by a fixing member 74, and is connected to each notch (225, 225, 225) of the inner glass plate 22 without protruding from the end portions of both glass plates (21, 22). 226), the connection terminal can be fixed to the exposed portion. At this exposed portion, the connecting terminals of the cables extending from the power source of the automobile are connected by a fixing material such as solder, so that electricity can be passed through the heating wires 62 through the busbar portions 61 to heat them. become.

In addition, when anti-fogging and/or deicing by heating wires is not performed in an area other than the information acquisition area 23, the other area heating unit 6 may be omitted.

(material)
Next, the material for the heat generating layer will be described. The base material 41 may be a transparent film, and its material is not particularly limited. For example, the material of the base material 41 may be polyethylene terephthalate, polyethylene, polymethyl methacrylate, polyvinyl chloride, polyester, polyolefin, polycarbonate, polystyrene, polypropylene, nylon, or the like.

In addition, each bus bar portion (51, 61) and each heating wire (52A to 52C, 62) of each heating portion (5, 6) are made of copper (or, for example, copper plated with tin or the like), tungsten , silver, gold, aluminum, and alloys thereof. Here, each busbar portion (51, 61) and each heating line (52A to 52C, 62) may be made of the same material or may be made of different materials. However, copper is a material that is easy to process. Also, since copper is chemically stable, it can be processed using chemical processing methods. Furthermore, copper is an inexpensive material compared to silver and the like. Therefore, from the viewpoint of manufacturing cost, it is preferable to use copper as the material of each heating part (5, 6). In addition, by making each busbar portion (51, 61) also from copper, it is possible to prevent abnormal heat generation due to contact resistance that occurs when current flows across dissimilar materials.

When the busbar portions (51, 61) are made of copper, the shielding layer 3 is formed on the fourth surface 222 in this embodiment. Therefore, each busbar portion (51, 61) becomes visible from the outside of the vehicle. As a result, the appearance of the windshield 1 may deteriorate.

Therefore, when each busbar portion (51, 61) is formed of copper, the surface of each busbar portion (51, 61) on the outside of the vehicle, in other words, the surface in contact with the base material 41 is plated to obtain a black color. It is preferable to process to Thereby, even if the shielding layer 3 is formed on the fourth surface 222, it is possible to make it difficult to visually recognize each busbar portion (51, 61) from the outside of the vehicle.

Next, a method for forming each busbar portion (51, 61) and each heating wire (52A to 52C, 62) will be described. Each busbar portion (51, 61) and each heating wire (52A to 52C, 62) can be formed by arranging pre-formed thin wires (wires, etc.) on the substrate 41. FIG.

Further, in order to make the line width of each heating line (52A to 52C, 62) thinner, each heating line (52A to 52C, 62) may be formed by forming a pattern on the substrate 41. good. A method for forming a pattern on the base material 41 is not particularly limited, and various methods such as printing, etching, and transfer may be used.

At this time, each busbar portion 51 and each heating wire 52A to 52C can be formed separately, or they can be formed integrally. Similarly, each busbar portion 61 and each heating wire 62 can be formed separately, or they can be formed integrally. In addition, "integral" means that there is no break (seamless) between materials and there is no interface.

Furthermore, when a pattern is formed on the base material 41 by etching, as an example, each bus bar portion (51, 61) and each heating line (52A to 52C, 62) can be formed. First, a metal foil is dry-laminated on the substrate 41 via a primer layer. For example, copper can be used as the metal foil. Then, the metal foil is chemically etched using a photolithographic method, so that the busbar portions (51, 61) of the heating portions (5, 6) and the heating wires ( 52A-52C, 62) can each be integrally patterned.

In particular, when the line width of each heating line (52A to 52C, 62) is made small (for example, 15 μm or less), it is preferable to use a thin metal foil. Therefore, a thin metal layer (for example, 5 μm or less) is formed on the base material 41 by vapor deposition, sputtering, or the like, and then each bus bar portion (51, 61) and each heating line (52A to 52C, 62) are formed by photolithography. You may pattern by.

<Adhesive layer>
Next, each adhesive layer (42, 43) will be described. Both adhesive layers (42, 43) are sheet-like members for sandwiching the heat-generating layer and performing adhesion to each glass plate (21, 22). Each adhesive layer (42, 43) is formed to have approximately the same size as each glass plate (21, 22), and has cutouts of the same shape at positions corresponding to the cutouts 223 to 226 of the inner glass plate 22. is doing.

The material of each adhesive layer (42, 43) may be appropriately selected according to the embodiment. For example, polyvinyl butyral resin (PVB), ethylene vinyl acetate (EVA), or the like can be used as the material of each adhesive layer (42, 43). In particular, polyvinyl butyral resin is preferable because it is excellent in adhesion to each glass plate (21, 22) and penetration resistance. A surfactant layer may be provided between each adhesive layer (42, 43) and the heat-generating layer. Such a surfactant can modify the surfaces of both layers and improve the adhesion.

<Others>
The intermediate layer 4 according to this embodiment is configured as described above. Although the total thickness of the intermediate layer 4 is not particularly limited, it is preferably 0.3 mm to 6.0 mm, more preferably 0.5 mm to 4.0 mm, and 0.6 mm to 2.0 mm. is particularly preferred.

Further, the thickness of the base material 41 is preferably 0.01 mm to 2.0 mm, more preferably 0.031 mm to 0.6 mm. On the other hand, the thickness of each adhesive layer (42, 43) is preferably larger than the thickness of the heat generating layer, specifically, preferably 0.1 mm to 2.0 mm, more preferably 0.1 mm to 1.0 mm. is more preferable. In addition, in order to enhance the adhesion between the adhesive layer 43 arranged on the inner glass plate 22 side and the base material 41, each bus bar portion (51, 61) and each heating wire (52A to 52C, 62 ) can be 1 μm to 500 μm, preferably 5 μm to 100 μm, more preferably 5 μm to 15 μm.

The thickness of the heating layer and each adhesive layer (42, 43) can be measured, for example, as follows. First, a cross section of the laminated glass 2 is enlarged 175 times and displayed by a microscope (for example, VH-5500 manufactured by Keyence Corporation). Then, the thicknesses of the heating layer and the adhesive layers (42, 43) are visually identified and measured. At this time, in order to eliminate variations due to visual observation, the number of measurements is set to 5, and the average value is taken as the thickness of the heat generating layer and each adhesive layer (42, 43).

The thickness of the heating layer and the adhesive layers (42, 43) of the intermediate layer 4 may not be uniform over the entire surface, and may be wedge-shaped for laminated glass used in head-up displays, for example. In this case, the thickness of the heating layer and each adhesive layer (42, 43) of the intermediate layer 4 is measured at the point where the thickness is the smallest, that is, the lowest side of the laminated glass. If the intermediate layer 4 is wedge-shaped, the outer glass pane 21 and the inner glass pane 22 are arranged at an angle to each other. Both glass panes (21, 22) of the laminated glass 2 may thus be arranged tilted to each other rather than parallel. For example, an intermediate layer 4 using a heating layer and adhesive layers (42, 43) whose thickness increases at a rate of change of 3 mm or less per meter may be used.

[Shooting device]
Next, the photographing device 8 will be described. The photographing device 8 is appropriately configured with a lens system, an image sensor, etc. so as to be able to photograph the situation outside the vehicle. An image acquired by the photographing device 8 is sent to the image processing device 81 . The image processing device 81 analyzes the type of subject, etc., based on the image acquired by the photographing device 8 . For example, the type of subject can be estimated by a known image analysis method such as pattern recognition.

The image processing device 81 is configured as a computer having a storage unit, a control unit, an input/output unit, etc. so as to perform such image analysis and present the results to the user (driver). Such an image processing apparatus 81 may be a general-purpose apparatus such as a PC (Personal Computer), a tablet terminal, or the like, as well as an apparatus designed exclusively for the service provided.

§2 Manufacturing Method Next, a manufacturing method of the windshield 1 according to the present embodiment will be described. The windshield 1 according to the present embodiment is manufactured by preparing an outer glass plate 21 and an inner glass plate 22 that constitute the laminated glass 2 and sandwiching the intermediate layer 4 between the two glass plates (21, 22). can be done. Hereinafter, the production of the laminated glass 2 will be described in order. The method for manufacturing the windshield 1 described below is merely an example, and each step may be changed as much as possible. Further, in the manufacturing process described below, steps can be omitted, replaced, or added as appropriate according to the embodiment.

First, a method for manufacturing the laminated glass 2 will be described with reference to FIG. FIG. 7 illustrates a production line for the laminated glass 2. As shown in FIG. As illustrated in FIG. 7, the manufacturing line for the laminated glass 2 comprises a ring-shaped mold 200, a carrier 201 for conveying the mold 200, and a heating furnace 202 in order to bend the laminated glass 2. and a slow cooling furnace 203 .

Before bending the laminated glass 2, each flat glass plate (21, 22) is prepared, and each prepared glass plate (21, 22) is cut into a predetermined shape. Then, the fourth surface 222 of the inner glass plate 22 is printed (applied) with the ceramic forming the shielding layer 3 by screen printing or the like.

The ceramic printed in each area is then dried as appropriate. Then, after drying the ceramic, the outer glass plate 21 and the inner glass plate 22 are vertically superimposed so that the second surface 212 and the third surface 221 face each other to form a flat laminated glass 20, The formed flat plate-shaped laminated glass 20 is placed on the mold 200 . The mold 200 is placed on a carriage 201 , and the carriage 201 passes through a heating furnace 202 and a slow cooling furnace 203 in order with the laminated glass 20 placed on the mold 200 .

When heated to near the softening point temperature in the heating furnace 202, both the glass plates (21, 22) are bent downward from the peripheral edges due to their own weight, and formed into curved surfaces. Subsequently, the two glass plates (21, 22) are transferred from the heating furnace 202 to the slow cooling furnace 203 and subjected to slow cooling. After that, both glass plates (21, 22) are taken out of the slow cooling furnace 203 and allowed to cool.

After the two glass plates (21, 22) are formed in this manner, the intermediate layer 4 is sandwiched between the two glass plates (21, 22). Specifically, first, the outer glass plate 21, the adhesive layer 42, the heat generating layer, the adhesive layer 43, and the inner glass plate 22 are laminated in this order. At this time, the surface of the heating layer on which the information acquisition area heating section 5 and the other area heating section 6 are formed faces the adhesive layer 43 side.

Further, the upper and lower ends of the heat generating layer are arranged inside the cutouts 223 to 226 of the inner glass plate 22 in the plane direction. Furthermore, the cutouts of each adhesive layer (42, 43) are aligned with the respective cutouts 223-226 of the inner glass plate 22. As shown in FIG. As a result, the outer glass plate 21 is exposed from the cutouts 223 to 226 of the inner glass plate 22 .

Subsequently, connecting members (71, 73) are inserted between the heat-generating layer and the adhesive layer 43 through the cutouts 223-226. At this time, solder having a low melting point is applied to the connection members (71, 73) as the fixing members (72, 74), and this solder is placed on the busbar portions (51, 61). make it

In this way, a laminate is produced in which both glass plates (21, 22), the intermediate layer 4, and the connecting members (71, 73) are laminated. This laminate is placed in a rubber bag and preliminarily adhered at about 70 to 110° C. while vacuum suction is applied. Other pre-bonding methods are possible, and the following method can also be adopted. For example, the laminate is heated at 45-65° C. in an oven. Next, this laminate is pressed with rolls at 0.45 to 0.55 MPa. Subsequently, this laminate is heated again in an oven at 80 to 105° C. and then pressed again with a roll at 0.45 to 0.55 MPa. Thus, pre-bonding is completed.

Next, final adhesion is performed. The pre-bonded laminate is subjected to main bonding in an autoclave, for example, at 8-15 atmospheres and 100-150°C. Specifically, for example, the main adhesion can be performed under the conditions of 14 atmospheres and 135°C. Through the above pre-bonding and final bonding, the bonding layers (42, 43) are bonded to the glass plates (21, 22) with the heat-generating layer sandwiched therebetween. Also, the solder of each connecting member (71, 73) is melted, and each connecting member (71, 73) is fixed to each busbar portion (51, 61). Thus, the windshield 1 according to this embodiment is manufactured.

The windshield 1 manufactured as described above is attached to the vehicle body, and connection terminals are fixed to the connection members (71, 73). After that, when each connection terminal is energized, electricity flows through each heating wire (52A to 52C, 62) through each connection member (71, 73) and each bus bar portion (51, 61), generating heat. This can remove fogging and/or ice from the information acquisition area 23 and other areas.

<Features>
As described above, in the windshield 1 according to the present embodiment, the information acquisition region 23 is arranged adjacently below (inside in the surface direction) the band-shaped region 31 of the shielding layer 3 along the upper edge of the laminated glass 2. , a photographing device 8 is installed in the vehicle. The busbars 51 of the information acquisition area heating unit 5 for removing fogging and/or ice from the information acquisition area 23 are arranged side by side in the horizontal direction within the band-shaped area 31 adjacent above the information acquisition area 23. be done. As a result, both busbar portions 51 are hidden by the band-shaped area 31, so that the shielding layer 3 does not need to be provided in the area around the information acquisition area 23 except for the area above the information acquisition area 23. FIG. That is, instead of arranging the busbar portions 51 so as to sandwich the information acquisition area 23, in the present embodiment, by arranging both busbar portions 51 in an area in one direction from the information acquisition area 23, other The shielding layer 3 may or may not be provided in the region in the direction of . Thereby, in this embodiment, the degree of freedom in designing the shielding layer 3 can be increased.

§3 Modifications Although the embodiments of the present invention have been described in detail, the above descriptions are merely examples of the present invention in every respect. It goes without saying that various modifications and variations can be made without departing from the scope of the invention. For example, regarding each component of the windshield 1, the component may be omitted, replaced, or added as appropriate according to the embodiment. Also, the shape and size of each component of the windshield 1 may be appropriately determined according to the embodiment. For example, the following changes are possible. In addition, below, the same code|symbol is used regarding the component similar to the said embodiment, and description is abbreviate|omitted suitably.

<3.1>
For example, in the shielding layer 3 according to the above-described embodiment, the band-shaped region 31 is set in the portion along the upper edge of the laminated glass 2, and the pair of busbar portions 51 are arranged side by side in the horizontal direction so as to be included in the portion. there is However, the position where the band-shaped region 31 is set does not have to be limited to such an example, and may be appropriately selected according to the embodiment.

For example, the strip regions 31 may be set along the lower edge, left edge, and right edge of the laminated glass 2 . Even in this case, the information acquisition area 23 can be arranged inside the band-like area 31 in the plane direction. For example, when the band-shaped region 31 is set along the lower edge of the laminated glass 2 , the information acquisition region 23 can be arranged above and adjacent to the band-shaped region 31 .

Here, in FIG. 3, the belt-like region 31 is formed in a rectangular shape extending in the left-right direction. However, this strip-shaped region 31 is a region for shielding the pair of busbar portions 51 arranged side by side, and it is sufficient that it extends in at least one direction. Therefore, the shape of the band-shaped region 31 may not be rectangular, and may be appropriately selected according to the embodiment.

Further, for example, in the above embodiment, the information acquisition area heating section 5 has three heating wires 52A to 52C. However, the number of heating wires included in the information acquisition area heating section 5 may not be limited to three, and may be two, or may be four or more. The number of heating wires provided in the information acquisition area heating section 5 may be appropriately selected according to the embodiment. Each heating line is connected in parallel to the busbar portion 51 . As described above, the information acquisition area heating unit 5 includes a plurality of heating wires, so that even if one of the heating wires breaks, the information acquisition region 23 can be heated by the other heating wires.

Further, as shown in FIG. 8, in the above embodiment, the heating wires 52A to 52C extend linearly, and adjacent heating wires have portions extending parallel to each other. FIG. 8 is an enlarged view schematically illustrating the information acquisition area heating section 5 according to this embodiment. As shown in FIG. 8, adjacent first heating wires 52A and second heating wires 52B extend parallel to each other in three portions 521A to 521C. Similarly, the adjacent second heating wire 52B and third heating wire 52C extend parallel to each other in each of the three portions 522A-522C. The inventors have found that the presence of such a portion causes the following phenomenon.

That is, light diffraction occurs at the ends of the heating wires 52A to 52C. This may result in constructive or destructive light depending on the position, which may adversely affect the photographing by the photographing device 8 . Therefore, as shown in FIG. 9, wires were arranged in parallel, light was passed through the area where the wires were arranged, and it was confirmed how the light was diffracted at the end of each wire. The conditions of each wire and light source are as follows.

(wire condition)
・Line width: 10 μm
・Pitch (interval between adjacent wires): 2mm
(Conditions of light source)
・Type of light source: Halogen lamp ・Placement: 7m away from the wire

FIG. 10 shows the results of the experiment. As shown in FIG. 10, it has been found that when straight wires are arranged in parallel, a line pattern with high light intensity is generated in one direction. In other words, it has been found that if the portions 522A to 522C as described above exist, there is a possibility that the imaging by the imaging device 8 may be adversely affected.

Therefore, as shown in FIG. 11, the same experiment as described above was conducted with the wire having a wavy shape such as a sine wave (angle: θ). The wire conditions (line width, pitch) and the light source conditions (light source type, arrangement) were the same as above. θ indicates the angle between the tangent line at the point of inflection (center of amplitude) of the heating wire and the horizontal line.

FIG. 12 shows the results of the experiment. As shown in FIG. 12, it was found that when the wires are wavy, light diffraction occurs at the ends of each wire, but the directions in which light is strengthened can be dispersed in multiple directions. That is, it was found that the light intensity of the pattern generated in each direction can be weakened, thereby reducing the possibility that the diffraction of light generated at the end of the wire adversely affects the photographing by the photographing device 8.

Therefore, when at least one of the heating wires 52A to 52C adjacent to each other has a portion extending parallel to each other, the parallel extending portions of the adjacent heating wires may be formed in a wavy shape. For example, as illustrated in FIGS. 13 and 14, each heating wire may be formed in a wavy shape.

FIG. 13 is an enlarged view schematically illustrating an information acquisition area heating section 5A according to this modification. The heating wires 53A to 53C are configured in the same manner as the heating wires 52A to 52C according to the above-described embodiment, except that they are wavy. Here, in the modification shown in FIG. 13, the adjacent first heating wire 53A and second heating wire 53B extend parallel to each other in three portions 531A to 531C. In each of the portions 531A to 531C, the adjacent first heating wire 53A and second heating wire 53B are formed in the same sine wave pattern. Adjacent second heating wire 53B and third heating wire 53C extend parallel to each other in three portions 532A to 532C. In each of the portions 532A to 532C, the adjacent second heating wire 53B and third heating wire 53C are formed in the same sinusoidal pattern. As a result, as shown in FIG. 12, it is possible to reduce the possibility that the diffraction of light generated at the ends of the heating wires will adversely affect the photographing of the photographing device 8 .

Also, as illustrated in FIG. 14, the wavy patterns of the parallel extending portions of adjacent heating wires may be offset from each other. FIG. 14 illustrates a form in which the sinusoidal patterns of the heating wires 53A to 53C are shifted. By displacing the wavy patterns of the parallel portions of adjacent heating wires in this way, it is possible to further prevent the occurrence of a filamentary pattern with high light intensity as shown in FIG. As a result, it is possible to further reduce the possibility that the diffraction of light occurring at the ends of the heating wires will adversely affect the photographing of the photographing device 8 .

In addition, if a filamentary pattern having a high light intensity as described above occurs, an edge of the filamentary pattern occurs in an image captured using the light incident on the imaging device 8. For example, , errors tend to occur in image processing such as pattern recognition. On the other hand, by making the heating wires wavy as described above, the light passing between the heating wires can be flattened. It is possible to suppress the edge of the pattern of the filament from occurring inside. As a result, it is possible to reduce the possibility that an error will occur when the predetermined image processing is applied to the image obtained by the photographing device 8 . Therefore, when applying predetermined image processing to the image obtained by the photographing device 8, it is very difficult to suppress the generation of linear patterns with high light intensity by making each heating line wavy as described above. important to

The same applies to each heating wire 62 of the other area heating unit 6 . Therefore, at least the portions of each heating wire 62 that extend in parallel with adjacent heating wires may be formed in a wavy shape, or the patterns of the wavy portions may be shifted from each other. As described above, by forming each heating line (53A to 53C, 62) in a wavy shape, it is possible to prevent the generation of linear patterns with high light intensity due to the diffraction of light as described above. The area where the wires (53A-53C, 62) are arranged can be easily heated uniformly. The shape of each heating wire (53A to 53C, 62) need not be limited to the linear shape and wave shape as described above, and may be appropriately selected according to the embodiment.

<3.2>
Further, for example, in the above embodiment, the information acquisition area heating section 5 and the other area heating section 6 are arranged in the intermediate layer 4 between the outer glass plate 21 and the inner glass plate 22 . However, the arrangement of the information acquisition area heating section 5 and the other area heating section 6 need not be limited to such an example, and may be appropriately selected according to the embodiment. For example, the information acquisition area heating section 5 and the other area heating section 6 may be arranged on either surface of the outer glass plate 21 or the inner glass plate 22 .

The information acquisition area heating section 5 and the other area heating section 6 can be arranged on either surface of the outer glass plate 21 or the inner glass plate 22 by various methods. For example, when molding the laminated glass 2, the information acquisition area heating unit 5 is formed by screen printing or the like on either surface of the outer glass plate 21 or the inner glass plate 22 (typically, the fourth surface 222). And the pattern of the other area heating unit 6 is printed. By baking the pattern in the same manner as the shielding layer 3, the information acquisition area heating section 5 and the other area heating section 6 can be formed.

15 and 16A to 16C, the information acquisition area heating section 5 and the other area heating section 6 can be arranged on either surface of the outer glass plate 21 or the inner glass plate 22. can. FIG. 15 illustrates a transfer sheet used for transfer in the information acquisition area heating section 5 and the other area heating section 6. As shown in FIG. 16A to 16C illustrate the process of forming the information acquisition area heating section 5 and the other area heating section 6 using the transfer sheet.

First, a transfer sheet as illustrated in FIG. 15 is prepared. The transfer sheet exemplified in FIG. 15 includes a release film 11, a pattern of the information acquisition area heating section 5 and the other area heating section 6 formed by screen printing or the like thereon, and arranged so as to cover the pattern. and an adhesive layer 12 . The release film 11 may be a known one, and the information acquisition area heating section 5 and the other area heating section 6 are those described above. For the adhesive layer 12, resin adhesives such as acrylic, methyl cellulose, nitrocellulose, ethyl cellulose, vinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, and polyester can be used. Note that the adhesive layer 12 may be covered with a peelable protective film or the like until the transfer.

Next, as shown in FIG. 16A, after the adhesive layer 12 of this transfer sheet is attached to either surface of the molded laminated glass 2, the release film 11 is peeled off. As a result, as shown in FIG. 16B , patterns of the adhesive layer 12 , the information acquisition area heating section 5 and the other area heating section 6 are arranged in this order on the surface of the laminated glass 2 . After that, when the laminated glass 2 is fired, the adhesive layer 12 is melted, and the information acquisition area heating section 5 and the other area heating section 6 are baked on the surface of the laminated glass 2 as shown in FIG. 16C. For example, when an acrylic adhesive is used as the adhesive layer 12, the information acquisition area heating section 5 and the other area heating section 6 are transferred to the laminated glass 2 by baking at about 400 to 700° C. for about 3 minutes. can do. The configuration of the transfer sheet is not limited to the above example, and may be appropriately selected according to the embodiment as long as the information acquisition area heating section 5 and the other area heating section 6 can be transferred. good.

Forming the information acquisition area heating section 5 and the other area heating section 6 from the transfer sheet as described above has the following advantages. First, it is easier and more flexible to form the patterns of the information acquisition area heating section 5 and the other area heating section 6 on the release film 11 than to form them directly on the laminated glass 2 . Therefore, production of highly structured patterns, production of laminates, and the like are facilitated. Next, if a large number of such transfer sheets are produced, the productivity in forming the information acquisition area heating section 5 and the other area heating section 6 on the laminated glass 2 is improved. Furthermore, the information acquisition area heating section 5 and the other area heating section 6 can also be attached to uneven surfaces.

<3.3>
Further, for example, as illustrated in FIG. 17, an anti-fogging film 9 may be attached to the information acquisition area 23 according to the above embodiment. FIG. 17 illustrates a windshield 1C with an antifogging film 9 attached to the information acquisition area 23. As shown in FIG.

In the windshield 1C illustrated in FIG. 17, the antifogging film 9 is attached to the fourth surface 222 of the inner glass plate 22 so as to be included in the information acquisition area 23 in the viewing direction. The type of the anti-fogging film 9 is not particularly limited as long as it exhibits the anti-fogging effect of the laminated glass 2, and known ones can be used. In general, types of anti-fogging films include a hydrophilic type that forms a water film on the surface of water generated from water vapor, a water-absorbing type that absorbs water vapor, and a water-repellent type that repels water droplets generated from water vapor. Any type can be used for the antifogging film 9 .

This makes it possible to make the information acquisition area 23 less foggy. Further, for example, in order to remove the fogging of the information acquisition area 23 by the information acquisition area heating unit 5, it takes a certain amount of time until the heating wires 52A to 52C are energized and warmed up. Therefore, if the information acquisition area 23 repeatedly fogs up, the loss of time for removing the fogging increases accordingly. On the other hand, according to the modification, the information acquisition area 23 can be made relatively difficult to fog up. It can be reduced, and the loss of time can be reduced accordingly.

In addition, in the modification, the anti-fogging film 9 is directly attached to the fourth surface 222 of the inner glass plate 22 . However, the arrangement of the antifogging film 9 need not be limited to such an example, and may be appropriately selected according to the embodiment. For example, after disposing the anti-fogging film 9 on a sheet-like base material, this base material can be attached to the laminated glass 2 with a transparent adhesive. Alternatively, the adhesive, the base material, and the antifogging film 9 can be laminated in this order. The substrate can be formed from a transparent resin sheet such as polyethylene or polyethylene terephthalate.

Moreover, the antifogging film 9 can be configured as follows, for example. That is, the anti-fogging film 9 can be configured to contain a water-repellent group and a metal oxide component, and preferably further contain a water-absorbing resin. The antifogging film 9 may further contain other functional components as necessary. Any type of water-absorbent resin can be used as long as it can absorb and retain water. The water-repellent group can be supplied to the antifogging film from a metal compound having a water-repellent group (water-repellent group-containing metal compound). The metal oxide component can be supplied to the antifogging film from a water-repellent group-containing metal compound, other metal compounds, metal oxide fine particles, and the like. Each component will be described below.

[Water absorbent resin]
First, the water absorbent resin will be explained. As the water absorbing resin, at least one selected from the group consisting of urethane resin, epoxy resin, acrylic resin, polyvinyl acetal resin, and polyvinyl alcohol resin can be exemplified. Urethane resins include polyurethane resins composed of polyisocyanate and polyol. Preferred polyols are acrylic polyols and polyoxyalkylene polyols. Examples of epoxy-based resins include glycidyl ether-based epoxy resins, glycidyl ester-based epoxy resins, glycidylamine-based epoxy resins, and cycloaliphatic epoxy resins. Preferred epoxy resins are cycloaliphatic epoxy resins. A polyvinyl acetal resin (hereinafter simply referred to as "polyacetal"), which is a preferred water absorbent resin, will be described below.

Polyvinyl acetal can be obtained by condensation reaction of polyvinyl alcohol with aldehyde to acetalize it. Acetalization of polyvinyl alcohol may be carried out using a known method such as a precipitation method using an aqueous medium in the presence of an acid catalyst, or a dissolution method using a solvent such as alcohol. Acetalization can also be carried out in parallel with the saponification of polyvinyl acetate. The degree of acetalization is preferably 2 to 40 mol %, more preferably 3 to 30 mol %, especially 5 to 20 mol %, and in some cases 5 to 15 mol %. The degree of acetalization can be measured, for example, by ¹³ C nuclear magnetic resonance spectroscopy. A polyvinyl acetal having a degree of acetalization within the above range is suitable for forming an anti-fogging film having good water absorption and water resistance.

The average degree of polymerization of polyvinyl alcohol is preferably 200-4500, more preferably 500-4500. A high average degree of polymerization is advantageous for forming an anti-fogging film with good water absorption and water resistance, but if the average degree of polymerization is too high, the viscosity of the solution becomes too high, which may interfere with the formation of the film. be. The degree of saponification of polyvinyl alcohol is preferably 75 to 99.8 mol %.

Aldehydes to be condensed with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. In addition, benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl group-substituted benzaldehyde; chlorobenzaldehyde, other halogen atom-substituted benzaldehyde; hydroxyl group, alkoxy group, amino group, alkyl such as cyano group Aromatic aldehydes such as substituted benzaldehyde in which a hydrogen atom is substituted by a functional group other than the group; condensed aromatic ring aldehydes such as naphthaldehyde and anthraldehyde. A highly hydrophobic aromatic aldehyde is advantageous in forming an antifogging film with a low degree of acetalization and excellent water resistance. The use of an aromatic aldehyde is also advantageous in forming a highly water-absorbing film while leaving many hydroxyl groups. The polyvinyl acetal preferably contains an acetal structure derived from aromatic aldehydes, especially benzaldehyde.

The content of the water-absorbent resin in the antifogging film is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% by mass or more, from the viewpoint of film hardness, water absorption and antifogging properties. It is 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 85% by mass or less.

[Water-repellent group]
Next, the water-repellent group will be explained. The water-repellent group facilitates both strength and anti-fogging properties of the anti-fogging film, and contributes to ensuring the straightness of incident light even if water droplets are formed on the surface of the film by making it hydrophobic. . In order to sufficiently obtain the effect of the water-repellent group, it is preferable to use a water-repellent group having high water repellency. Preferred water-repellent groups are (1) a chain or cyclic alkyl group having 3 to 30 carbon atoms, and (2) a chain or cyclic group having 1 to 30 carbon atoms in which at least part of the hydrogen atoms are substituted with fluorine atoms. It is at least one selected from alkyl groups (hereinafter sometimes referred to as "fluorine-substituted alkyl groups").

Regarding (1) and (2), the chain or cyclic alkyl group is preferably a chain alkyl group. The chain alkyl group may be a branched alkyl group, but is preferably a straight chain alkyl group. Alkyl groups having more than 30 carbon atoms may make the antifogging film cloudy. From the viewpoint of the balance between anti-fogging properties, strength and appearance of the film, the number of carbon atoms in the chain alkyl group is preferably 20 or less, such as 1 to 8, or, for example, 4 to 16, preferably 4 to 8. be. Particularly preferred alkyl groups are linear alkyl groups having 4 to 8 carbon atoms, such as n-pentyl, n-hexyl, n-heptyl and n-octyl groups. Regarding (2), the fluorine-substituted alkyl group may be a group in which only a part of the hydrogen atoms of a chain or cyclic alkyl group are substituted with fluorine atoms, and all hydrogen atoms of the chain or cyclic alkyl group may be a group substituted with a fluorine atom, such as a linear perfluoroalkyl group. Since the fluorine-substituted alkyl group has high water repellency, a sufficient effect can be obtained by adding a small amount. However, if the content of the fluorine-substituted alkyl group is too high, it may separate from other components in the coating solution for forming the film.

(Hydrolyzable metal compound having water-repellent group)
In order to incorporate the water-repellent group into the antifogging film, a metal compound having a water-repellent group (water-repellent group-containing metal compound), especially a metal compound having a water-repellent group and a hydrolyzable functional group or a halogen atom ( water-repellent group-containing hydrolyzable metal compound) or its hydrolyzate may be added to the coating solution for forming the film. In other words, the water-repellent group may be derived from the water-repellent group-containing hydrolyzable metal compound. As the water-repellent group-containing hydrolyzable metal compound, a water-repellent group-containing hydrolyzable silicon compound represented by the following formula (I) is suitable.
_{RmSiY4 -m} (I)
Here, R is a water-repellent group, that is, a chain or cyclic alkyl group having 1 to 30 carbon atoms in which at least part of the hydrogen atoms may be substituted with fluorine atoms, and Y is a hydrolyzable functional group. is a group or a halogen atom, and m is an integer of 1-3. The hydrolyzable functional group is, for example, at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group and an amino group, preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. An alkenyloxy group is, for example, an isopropenoxy group. A halogen atom is preferably chlorine. The functional groups exemplified here can also be used as "hydrolyzable functional groups" described later. m is preferably 1-2.

A compound of formula (I), upon completion of hydrolysis and polycondensation, provides a component of formula (II) below.
_{RmSiO (4-m)/2} (II)
Here, R and m are as described above. After hydrolysis and polycondensation, the compound represented by formula (II) actually forms a network structure in which silicon atoms are linked to each other via oxygen atoms in the antifogging film.

Thus, the compound represented by formula (I) is hydrolyzed or partially hydrolyzed, and at least partially polycondensed so that the silicon atoms and oxygen atoms are alternately connected and three-dimensionally A network structure of spreading siloxane bonds (Si—O—Si) is formed. A water-repellent group R is connected to the silicon atoms included in this network structure. In other words, the water-repellent group R is fixed to the network structure of siloxane bonds via the bond R—Si. This structure is advantageous for uniformly dispersing the water-repellent groups R in the film. The network structure may contain a silica component supplied from a silicon compound (eg, tetraalkoxysilane, silane coupling agent) other than the water-repellent group-containing hydrolyzable silicon compound represented by formula (I). For forming an antifogging film with a silicon compound having no water-repellent group and having a hydrolyzable functional group or a halogen atom (a hydrolyzable silicon compound not containing a water-repellent group) together with a hydrolyzable silicon compound containing a water-repellent group. When blended in the coating liquid of (1), a network structure of siloxane bonds containing silicon atoms bonded to water-repellent groups and silicon atoms not bonded to water-repellent groups can be formed. With such a structure, it becomes easy to independently adjust the content of the water-repellent group and the content of the metal oxide component in the antifogging film.

When the anti-fogging film contains a water-absorbing resin, the water-repellent group improves the anti-fogging performance by improving the water vapor permeability on the surface of the anti-fogging film containing the water-absorbing resin. Since the two functions of water absorption and water repellency contradict each other, the water-absorbing material and the water-repellent material have conventionally been assigned to separate layers, but the water-repellent group contained in the anti-fogging film is To improve the antifogging property of an antifogging film by eliminating the uneven distribution of water in the vicinity of the surface of the cloudy layer and extending the time until dew condensation occurs. The effect will be described below.

The water vapor that has penetrated into the anti-fogging film containing the water-absorbing resin forms hydrogen bonds with the hydroxyl groups of the water-absorbing resin, etc., and is retained in the form of bound water. As the amount increases, the water vapor changes from the form of bound water to the form of semi-bound water, and finally comes to be retained in the form of free water retained in the voids in the antifogging film. In the antifogging film, the water-repellent group prevents the formation of hydrogen bonds and facilitates the dissociation of the formed hydrogen bonds. If the content of the water-absorbing resin is the same, there is no difference in the number of hydroxyl groups capable of hydrogen bonding in the film, but the water-repellent groups reduce the rate of formation of hydrogen bonds. Therefore, in an antifogging film containing a water-repellent group, water will eventually be retained in the film in one of the above forms. can spread. Also, the water that is once retained is relatively easily dissociated and easily moves to the bottom of the membrane in the form of water vapor. As a result, the distribution of the amount of retained water in the thickness direction of the film becomes relatively uniform from the vicinity of the surface to the bottom of the film. That is, the entire thickness direction of the anti-fogging film can be effectively used to absorb water supplied to the film surface, so that water droplets are less likely to condense on the surface and the anti-fogging property is enhanced.

On the other hand, in a conventional anti-fogging film containing no water-repellent groups, water vapor that has penetrated into the film is very easily retained in the form of bound water, semi-bonded water or free water. Therefore, infiltrated water vapor tends to be retained near the surface of the film. As a result, the water content in the film is extremely high near the surface and decreases rapidly as one progresses to the bottom of the film. In other words, although the bottom portion of the film can still absorb water, the near surface of the film is saturated with water and condenses as water droplets, resulting in limited anti-fogging properties.

When a water-repellent group-containing hydrolyzable silicon compound (see formula (I)) is used to introduce a water-repellent group into the antifogging film, a strong siloxane bond (Si--O--Si) network structure is formed. Formation of this network structure is advantageous from the viewpoint of improving not only wear resistance but also hardness, water resistance, and the like.

The water-repellent group should be added so that the contact angle of water on the surface of the antifogging film is 70 degrees or more, preferably 80 degrees or more, and more preferably 90 degrees or more. For the contact angle of water, a value measured by dropping a 4 mg water droplet on the surface of the film is adopted. In particular, when a methyl group or an ethyl group, which have relatively low water repellency, is used as the water repellent group, it is preferable to add such a water repellent group to the antifogging film that the contact angle of water falls within the above range. Although the upper limit of the contact angle of water is not particularly limited, it is, for example, 150 degrees or less, or, for example, 120 degrees or less, or further 105 degrees or less. The water-repellent groups are preferably contained uniformly in the antifogging film so that the water contact angle is within the above range over the entire surface area of the antifogging film.

Here, the relationship between the contact angle of water and the antifogging film 9 will be described with reference to FIGS. 18 and 19. FIG. FIGS. 18 and 19 show water droplets (90, 91) having different contact angles attached to the antifogging film 9. FIG. As shown in FIGS. 18 and 19, the area covered by the water droplets (90, 91) formed by condensing the same amount of water vapor on the surface of the antifogging film 9 is the contact area of the surface with water. It tends to become smaller as the angle increases. Also, the smaller the area covered by the water droplets (90, 91), the smaller the ratio of the area where the light incident on the antifogging film 9 is scattered. Therefore, the anti-fogging film 9 having a large water contact angle due to the presence of water-repellent groups is advantageous in maintaining the straightness of transmitted light when water droplets are formed on its surface.

The antifogging film 9 preferably contains a water-repellent group so that the contact angle of water falls within the preferred range described above. When the water-absorbent resin is contained, the anti-fogging film should be in the range of 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the water-absorbent resin. 10 parts by mass or less, preferably 5 parts by mass or less.

[Metal oxide component]
Next, the metal oxide component will be explained. The metal oxide component is, for example, an oxide component of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, preferably a Si oxide component (silica component ). When the water-absorbing resin is contained, the anti-fogging film contains 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and still more preferably 100 parts by mass of the water-absorbing resin. 1 part by mass or more, particularly preferably 5 parts by mass or more, optionally 7 parts by mass or more, if necessary 10 parts by mass or more, and 60 parts by mass or less, particularly 50 parts by mass or less, preferably 40 parts by mass or less, More preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and in some cases 18 parts by mass or less, the metal oxide component is preferably included. The metal oxide component is a component necessary for securing the strength of the film, especially the scratch resistance, but if the content is excessive, the anti-fogging property of the film decreases.

At least part of the metal oxide component may be a metal oxide component derived from a hydrolyzable metal compound or its hydrolyzate added to the coating liquid for forming the antifogging film. Here, the hydrolyzable metal compound includes a) a metal compound having a water-repellent group and a hydrolyzable functional group or a halogen atom (hydrolyzable metal compound containing a water-repellent group) and b) a water-repellent group-containing hydrolyzable metal compound. It is at least one selected from metal compounds having a hydrolyzable functional group or a halogen atom (water-repellent group-free hydrolyzable metal compounds). The metal oxide component derived from a) and/or b) is an oxide of the metal atoms that make up the hydrolyzable metal compound. The metal oxide component includes the metal oxide component derived from the metal oxide fine particles added to the coating liquid for forming the antifogging film, and the hydrolyzable metal compound or its and a metal oxide component derived from the hydrolyzate. Again, the hydrolyzable metal compound is at least one selected from a) and b) above. The above b), ie, the hydrolyzable metal compound having no water-repellent group, may contain at least one selected from tetraalkoxysilanes and silane coupling agents. The metal oxide fine particles and the above b) will be described below, except for the already explained above a).

(metal oxide fine particles)
The antifogging film 9 may further contain metal oxide fine particles as at least part of the metal oxide component. The metal oxide constituting the metal oxide fine particles is, for example, an oxide of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, preferably silica fine particles. be. Silica microparticles can be introduced into the membrane, for example, by adding colloidal silica. The metal oxide fine particles are excellent in transferring the stress applied to the antifogging film to the transparent article supporting the film, and have high hardness. Therefore, the addition of metal oxide fine particles is advantageous from the viewpoint of improving the wear resistance and scratch resistance of the antifogging film. In addition, when metal oxide fine particles are added to the antifogging film, minute voids are formed at the sites where the fine particles are in contact or close to each other, and water vapor is easily taken into the film through these voids. Therefore, the addition of metal oxide fine particles may act advantageously for improving the anti-fogging property. The metal oxide fine particles can be supplied to the antifogging film by adding preformed metal oxide fine particles to the coating liquid for forming the antifogging film.

If the average particle size of the metal oxide fine particles is too large, the film may become cloudy. From this point of view, the average particle size of the metal oxide fine particles is preferably 1 to 20 nm, particularly 5 to 20 nm. Here, the average particle size of the metal oxide fine particles is described in the state of primary particles. The average particle diameter of the metal oxide fine particles is determined by measuring the particle diameters of 50 arbitrarily selected fine particles by observation using a scanning electron microscope and adopting the average value. If the content of the metal oxide fine particles is excessively high, the water absorption of the entire film may decrease and the film may become cloudy. When the antifogging film contains a water absorbent resin, the metal oxide fine particles are 0 to 50 parts by weight, preferably 1 to 30 parts by weight, more preferably 2 to 30 parts by weight, and particularly It is preferably added in an amount of 5 to 25 parts by mass, and in some cases 10 to 20 parts by mass.

(Hydrolyzable metal compound having no water-repellent group)
Moreover, the anti-fogging film 9 may contain a metal oxide component derived from a hydrolyzable metal compound having no water-repellent group (hydrolyzable compound not containing a water-repellent group). A preferred hydrolyzable metal compound containing no water-repellent group is a hydrolyzable silicon compound having no water-repellent group. The hydrolyzable silicon compound having no water-repellent group is, for example, at least one silicon compound selected from silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane and aminosilane (provided that it does not have a water-repellent group), A silicon alkoxide having no water-repellent group is preferred. Isopropenoxysilane can be exemplified as the alkenyloxysilane.

The hydrolyzable silicon compound having no water-repellent group may be a compound represented by formula (III) below.
_SiY4 (III)
As described above, Y is a hydrolyzable functional group, preferably at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, an amino group and a halogen atom.

The water-repellent group-free hydrolyzable metal compound is hydrolyzed or partially hydrolyzed, and at least a part thereof is polycondensed to supply a metal oxide component in which metal atoms and oxygen atoms are bonded. This component firmly bonds the metal oxide fine particles and the water-absorbing resin, and can contribute to improving the wear resistance, hardness, water resistance, etc. of the anti-fogging film. When the anti-fogging film contains a water-absorbing resin, the metal oxide component derived from the hydrolyzable metal compound having no water-repellent group is 0 to 40 parts by mass, preferably 0.5 parts by mass, per 100 parts by mass of the water-absorbing resin. 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, particularly preferably 3 to 10 parts by mass, and in some cases 4 to 12 parts by mass.

A preferred example of the hydrolyzable silicon compound having no water-repellent group is tetraalkoxysilane, more specifically tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms. Tetraalkoxysilanes are, for example, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane and tetra-tert- It is at least one selected from butoxysilane.

If the content of the metal oxide (silica) component derived from tetraalkoxysilane becomes excessive, the antifogging properties of the antifogging film may deteriorate. This is partly due to the reduced flexibility of the antifogging membrane, which limits the swelling and shrinkage of the membrane as it absorbs and releases moisture. When the antifogging film contains a water absorbent resin, the metal oxide component derived from tetraalkoxysilane is 0 to 30 parts by weight, preferably 1 to 20 parts by weight, more preferably 3 parts by weight, based on 100 parts by weight of the water absorbent resin. It is preferable to add in a range of up to 10 parts by mass.

Another preferred example of a hydrolyzable silicon compound having no water-repellent group is a silane coupling agent. A silane coupling agent is a silicon compound having different reactive functional groups. The reactive functional groups are preferably partially hydrolyzable functional groups. A silane coupling agent is, for example, a silicon compound having an epoxy group and/or an amino group and a hydrolyzable functional group. Preferred silane coupling agents include glycidyloxyalkyltrialkoxysilanes and aminoalkyltrialkoxysilanes. In these silane coupling agents, the alkylene group directly bonded to the silicon atom preferably has 1 to 3 carbon atoms. Glycidyloxyalkyl groups and aminoalkyl groups contain hydrophilic functional groups (epoxy groups, amino groups), and therefore, although they contain alkylene groups, they are not water-repellent as a whole.

The silane coupling agent strongly binds the water-absorbent resin, which is an organic component, and the metal oxide fine particles, which are inorganic components, and can contribute to improving the wear resistance, hardness, water resistance, etc. of the anti-fogging film. However, if the content of the metal oxide (silica) component derived from the silane coupling agent becomes excessively large, the antifogging property of the antifogging film is lowered, and in some cases the antifogging film becomes cloudy. When the anti-fogging film contains a water absorbent resin, the metal oxide component derived from the silane coupling agent is 0 to 10 parts by weight, preferably 0.05 to 5 parts by weight, or more, relative to 100 parts by weight of the water absorbent resin. It is preferably added in the range of 0.1 to 2 parts by mass.

[Crosslinked structure]
The anti-fogging film 9 may also contain a crosslinked structure derived from a crosslinking agent, preferably at least one crosslinking agent selected from organic boron compounds, organic titanium compounds and organic zirconium compounds. Introduction of a crosslinked structure improves the abrasion resistance, scratch resistance, and water resistance of the antifogging film. From another point of view, the introduction of the crosslinked structure facilitates improving the durability of the antifogging film without degrading its antifogging performance.

When a cross-linked structure derived from a cross-linking agent is introduced into an anti-fogging film whose metal oxide component is a silica component, the anti-fogging film contains silicon as a metal atom and a metal atom other than silicon, preferably boron, titanium or zirconium, may contain

The type of the cross-linking agent is not particularly limited as long as it can cross-link the water absorbent resin used. Examples are given here only for organotitanium compounds. The organic titanium compound is, for example, at least one selected from titanium alkoxides, titanium chelate compounds and titanium acylates. Titanium alkoxides are, for example, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraoctoxide. Examples of titanium chelate compounds include titanium acetylacetonate, titanium acetoethyl acetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. Titanium lactate may be an ammonium salt (titanium lactate ammonium). Titanium acylate is, for example, titanium stearate. Preferred organotitanium compounds are titanium chelate compounds, particularly titanium lactate.

A preferred cross-linking agent when the water absorbent resin is polyvinyl acetal is an organic titanium compound, particularly titanium lactate.

[Other optional ingredients]
The anti-fogging film 9 may contain other additives. Examples of additives include glycols such as glycerin and ethylene glycol, which have the function of improving antifogging properties. Additives may be surfactants, leveling agents, UV absorbers, colorants, defoamers, preservatives, and the like.

[Thickness]
The film thickness of the antifogging film 9 may be appropriately adjusted according to the required antifogging properties and other factors. The thickness of the antifogging film 9 is preferably 1 to 20 μm, preferably 2 to 15 μm, particularly 3 to 10 μm.

[Deposition]
The anti-fogging film 9 is formed by applying a coating liquid for forming the anti-fogging film 9 onto a transparent article such as a transparent substrate, drying the applied coating liquid, and subjecting it to high-temperature and high-humidity treatment as necessary. A film can be formed by carrying out. Conventionally known materials and methods may be used for the solvent used for preparing the coating liquid and the coating method for the coating liquid.

In the step of applying the coating liquid, it is preferable to maintain the relative humidity of the atmosphere at less than 40%, more preferably at 30% or less. Keeping the relative humidity low prevents the membrane from absorbing too much moisture from the atmosphere. If a large amount of moisture is absorbed from the atmosphere, the remaining water that enters the matrix of the membrane may reduce the strength of the membrane.

The drying step of the coating liquid preferably includes an air-drying step and a heat-drying step involving heating. The air-drying step is preferably carried out by exposing the coating liquid to an atmosphere maintained at a relative humidity of less than 40%, more preferably 30% or less. The air-drying step can be performed as an unheated step, in other words at room temperature. When the coating liquid contains a hydrolyzable silicon compound, a dehydration reaction involving the silanol groups contained in the hydrolyzate of the silicon compound and the hydroxyl groups present on the transparent article progresses in the heat drying process. A matrix structure (network of Si—O bonds) consisting of silicon atoms and oxygen atoms develops.

In order to avoid decomposition of organic matter such as water absorbent resin, the temperature applied in the heat drying process should not be excessively high. A suitable heating temperature in this case is 300° C. or less, for example, 100 to 200° C., and the heating time is 1 minute to 1 hour.

When forming the anti-fogging film 9, a high-temperature and high-humidity treatment process may be carried out as appropriate. By carrying out the high-temperature and high-humidity treatment step, it becomes easier to achieve both antifogging properties and film strength. The high-temperature and high-humidity treatment step can be carried out, for example, by holding in an atmosphere of 50 to 100° C. and a relative humidity of 60 to 95% for 5 minutes to 1 hour. The high-temperature and high-humidity treatment step may be performed after the coating step and the drying step, or may be performed after the coating step and the air-drying step and before the heat-drying step. Particularly in the former case, a heat treatment step may be further carried out after the high temperature and high humidity treatment step. This additional heat treatment step can be performed, for example, by holding in an atmosphere of 80 to 180° C. for 5 minutes to 1 hour.

Moreover, the anti-fogging film 9 formed from the coating liquid may be washed and/or wiped with a damp cloth, if necessary. Specifically, it can be carried out by exposing the surface of the antifogging film 9 to a stream of water or wiping it with a cloth soaked with water. Pure water is suitable for the water used in these processes. Avoid using solutions containing detergents for cleaning. This step removes dust, stains, etc. adhering to the surface of the anti-fogging film 9 to obtain a clean coating film surface.

As is clear from the above description, preferred forms of the antifogging film 9 include the following. That is, the antifogging film 9 preferably contains 0.1 to 60 parts by mass of the metal oxide component and 0.05 to 10 parts by mass of the water repellent group with respect to 100 parts by mass of the water absorbent resin. At this time, the water-repellent group is a chain alkyl group having 1 to 8 carbon atoms, the water-repellent group is directly bonded to the metal atom constituting the metal oxide component, and the metal atom may be silicon. . At least a part of the metal oxide component is derived from the hydrolyzable metal compound or the hydrolyzate of the hydrolyzable metal compound added to the coating liquid for forming the antifogging film. The hydrolyzable metal compound may be at least one selected from hydrolyzable metal compounds having water-repellent groups and hydrolyzable metal compounds having no water-repellent groups. Furthermore, the hydrolyzable metal compound having no water-repellent group may contain at least one selected from tetraalkoxysilanes and silane coupling agents. By forming the anti-fogging film 9 in this manner, fogging of the information acquisition area 23 can be suppressed, and information outside the vehicle can be appropriately acquired by the information acquisition device. When the anti-fogging film 9 is arranged on the fourth surface 222, the information acquisition region heating unit 5 should not be in direct contact with the anti-fogging film 9, for example, as in the above embodiment. 5 is preferably located outside the fourth surface 222 . Thereby, deterioration of the antifogging film 9 can be prevented.

<3.4>
Further, for example, in the above-described embodiment, the shielding layer 3 is not provided around the information acquisition area 23 except for the area above the information acquisition area 23 (outside in the plane direction). However, if the shielding layer 3 is provided in the portion where the pair of busbar portions 51 are arranged in parallel, the shape of the shielding layer 3 may not be limited to such an example. A shielding layer 3 may be provided so as to surround the .

FIG. 20 schematically illustrates a windshield 1D provided with a shielding layer 3D so as to surround the information acquisition area 23D. As illustrated in FIG. 20, the shielding layer 3D according to this modification has a rectangular protruding region 32 that protrudes inward in the plane direction at the center of the portion along the upper side of the laminated glass 2 . This shielding layer 3D is similar to the shielding layer 3 of the above embodiment, except that it has protruding regions 32 . The information acquisition area 23D is provided as a transmissive window in the projecting area 32. As shown in FIG.

That is, the information acquisition area 23D is an area where the ceramic forming the shielding layer 3D is not partially applied, so that the information acquisition area 23D can be provided within the projecting area 32 . The photographing device 8 can photograph the situation outside the vehicle via this information acquisition area 23D.

In addition, in this modified example, a shielding layer 3D is provided all around the information acquisition area 23D. However, the shape of the shielding layer 3D need not be limited to such an example, and at least one of the left and right sides and the lower portion of the information acquisition area 23D may be omitted. That is, the portion of the shielding layer 3D where the busbar portion 51 is not arranged may be omitted.

<3.5>
Further, for example, in the above embodiment, the imaging device 8 is used as the information acquisition device. However, the information acquisition device is not limited to such an example as long as it is a device capable of acquiring information from outside the vehicle by irradiating and/or receiving light. may be selected. For example, as an information acquisition device, a visible light and/or infrared camera for measuring the inter-vehicle distance, a light receiving device such as an optical beacon that receives signals from outside the vehicle, a visible light and/or image that reads white lines on the road, etc. Various devices may be used, such as a camera using infrared.

Moreover, a plurality of information acquisition devices may be used, and a stereo camera having a plurality of photographing devices may be used as the information acquisition device. A known stereo camera can be used. In this case, a plurality of information acquisition areas 23 can be provided corresponding to a plurality of information acquisition devices and/or a plurality of imaging devices. Further, the information acquisition area heating section 5 may be provided in all of the plurality of information acquisition areas 23, or the information acquisition area heating section 5 may be provided in at least one of the plurality of information acquisition areas 23. FIG. Furthermore, one information acquisition area heating section 5 may be provided so as to include two or more information acquisition areas 23 . The number and arrangement of the information acquisition areas 23 and the number and arrangement of the information acquisition area heating units 5 may be appropriately selected according to the embodiment.

<3.6>
Further, for example, the glass plate of the windshield 1 according to the above-described embodiment is composed of laminated glass 2 in which an outer glass plate 21 and an inner glass plate 22 are bonded together via an intermediate layer 4 . However, the type of glass plate of the windshield 1 need not be limited to such an example, and may be appropriately selected according to the embodiment. The windshield 1 may be composed of, for example, one glass plate. Furthermore, in the above embodiment, the glass plate (laminated glass 2) of the windshield 1 is formed in a substantially trapezoidal shape. However, the shape of the glass plate of the windshield 1 need not be limited to such an example, and may be appropriately selected according to the embodiment.

<3.7>
Further, for example, in the above embodiment, the shielding layer 3 is laminated on the fourth surface 222 of the laminated glass 2 . However, the surface on which the shielding layer 3 is laminated may not be limited to such an example, and may be appropriately selected according to the embodiment. For example, the shielding layer 3 may be laminated on the second side 212 and/or the third side 221 of the laminated glass 2 .

<3.8>
Further, for example, in the above embodiment, the laminated glass 2 is formed into a curved shape by self-weight bending. However, the method of forming the laminated glass 2 may not be limited to such an example, and may be appropriately selected according to the embodiment. For example, the laminated glass 2 may be formed into a curved shape by known press molding.

<3.9>
Further, for example, in the above-described embodiment, the intermediate layer 4 includes a heat generating layer including the information acquisition area heating section 5 and the other area heating section 6, and a pair of adhesive layers (42, 43) sandwiching the heat generating layer, a total of three layers. consists of However, the configuration of the intermediate layer 4 need not be limited to such an example, and may be appropriately selected according to the embodiment. For example, either one of the pair of adhesive layers (42, 43) may be omitted, or the base material 41 may be omitted.

<3.10>
Further, for example, in the above embodiment, the shielding layer 3 has a single-layer structure. However, the shielding layer 3 may also have a multilayer structure. For example, the first ceramic layer is formed by laminating ceramic on the fourth surface 222 of the inner glass plate 22 . Next, a silver layer is formed by laminating silver on the first ceramic layer. Furthermore, a second ceramic layer is formed by laminating ceramic on this silver layer. Thereby, the shielding layer 3 having a three-layer structure can be formed. The shielding layer 3 of this three-layer structure can shield electromagnetic waves with a silver layer. A material having a composition shown in Table 2 below can be used for this silver layer.

＊１，主成分：ホウケイ酸ビスマス、ホウケイ酸亜鉛

*1, Main components: bismuth borosilicate, zinc borosilicate

<3.11>
Further, for example, in the above-described embodiment, each of the heating wires 52A to 52C is formed in a substantially U-shape. However, the shape of each heating wire 52A to 52C need not be limited to such an example, and may be appropriately formed so as to pass through the information acquisition area 23 and be connectable to both busbar portions 51. FIG. That is, each heating wire 52A to 52C has a shape that extends inward in the plane direction from one busbar portion 51, passes through the information acquisition region 23, is folded back, and extends toward the other busbar portion 51. It does not have to be limited. For example, each heating line may be formed as illustrated in FIG.

FIG. 21 is an enlarged view schematically illustrating an information acquisition area heating section 5E according to this modification. The information acquisition area heating section 5E has two heating lines (54A, 54B) arranged in parallel. The first heating wire 54A is arranged outside and the second heating wire 54B is arranged inside. Both of the heating wires (54A, 54B) extend from one busbar portion 51 toward the information acquisition region 23, pass through the information acquisition region 23, turn around and extend toward the other busbar portion 51 near the center, Each busbar portion 51 has a folded portion (541A, 541B) folded back. Thus, each heating wire may include a folded portion. As a result, even if the number of heating wires is small, the information acquisition area 23 can be evenly heated.

In addition, in this modification, the cross-sectional area of both heating wires (54A, 54B) may be the same. However, the first heating wire 54A arranged outside is longer than the second heating wire 54B arranged inside. Therefore, from the relational expressions of Equations 1 to 3, there is a possibility that the amount of heat generated by the first heating wire 54A arranged on the outer side will be smaller than that of the second heating wire 54B. Therefore, the cross-sectional area of the first heating wire 54A may be made larger than that of the second heating wire 54B so that the two heating wires (54A, 54B) generate substantially the same amount of heat.

1... windshield,
2... Laminated glass,
21... outer glass plate, 211... first surface, 212... second surface,
22... inner glass plate, 221... third surface, 222... fourth surface, 223 to 226... notch,
23... Information acquisition area,
3... Shielding layer, 31... Band-like region,
4 Intermediate layer 41 Base material 42/43 Adhesive layer
5... information acquisition area heating unit, 51... bus bar unit, 52A to 52C... heating wire,
6... other area heating part, 61... bus bar part, 62... heating wire,
71... Connecting material, 72... Fixing material, 73... Connecting material, 74... Fixing material,
8... photographing device, 81... image processing device,
9... anti-fogging film,
11... Release film, 12... Adhesive layer

Claims (10)

A windshield of an automobile in which an information acquisition device that acquires information from outside the vehicle by irradiating and/or receiving light can be arranged,
a glass plate having an information acquisition area facing the information acquisition device and through which the light passes;
A shielding layer that is provided on the glass plate and shields a field of view from outside the vehicle;
an information acquisition area heating unit having a pair of busbars and a plurality of heating wires and heating the information acquisition area;
with
The shielding layer includes a strip-shaped region extending along the edge of the glass plate,
The information acquisition area is arranged adjacent to the inside of the strip area in the plane direction,
Both busbar portions of the information acquisition area heating unit are arranged side by side so as to be included in the band-shaped area in the viewing direction,
Each heating wire of the information acquisition region heating section is connected in parallel to both busbar portions, extends inward in the plane direction from one busbar portion, passes over the information acquisition region, and is folded back to the other busbar portion. extending in the direction of
windshield. In the plurality of heating wires, the heating wire extending more inward in the surface direction has a larger cross-sectional area,
A windshield according to claim 1. At least one of the plurality of heating wires adjacent to each other has a portion extending parallel to each other,
Each of the parallel extending portions of the heating wires adjacent to each other is formed in a wavy shape,
A windshield according to claim 1 or 2. the wavy patterns of the parallel-extending portions of the adjacent heating wires are offset from each other;
A windshield according to claim 3. An anti-fogging film is attached to the information acquisition area,
A windshield according to any one of claims 1 to 4. The plurality of heating wires are made of copper,
A windshield according to any one of claims 1 to 5. Further comprising a non-region heating unit that has one or more heating wires and heats a region other than the information acquisition region,
A windshield according to any one of claims 1 to 6. The amount of heat generated per unit area of the information acquisition area heating unit and the amount of heat generated per unit area of the other area heating unit are different,
A windshield according to claim 7. The cross-sectional area of each heating wire of the information acquisition area heating unit is larger than that of the heating wire of the other area heating unit,
A windshield according to claim 8. The cross-sectional area of each heating wire of the information acquisition area heating unit is smaller than that of the heating wire of the other area heating unit.
A windshield according to claim 8.

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