JP7449994B2 - windshield - Google Patents

Description

The present invention relates to a windshield for a motor vehicle.

For example, in places where the temperature is low, the windshield of a car may fog up or even freeze due to the difference in temperature between the inside and outside of the car, which may impede driving. In response to this, various methods have been proposed for removing fog or ice from windshields. For example, Patent Document 1 proposes disposing a bus bar and a heating wire inside a windshield and removing fogging by the heat generated by the bus bar and heating wire.

Furthermore, in recent years, in-vehicle systems have been proposed in which a camera is installed inside the vehicle to photograph the situation outside the vehicle. This in-vehicle system analyzes images of objects captured by a camera to recognize oncoming vehicles, vehicles in front, pedestrians, traffic signs, lane boundaries, etc., and performs various functions such as alerting the driver of danger. Driving assistance can be provided.

However, while a shielding layer is generally provided along the periphery of the windshield to block the view from outside the vehicle, the camera of the in-vehicle system is installed near the support of the rearview mirror, etc. The shielding layer 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 obstructs the camera from taking pictures.

Therefore, Patent Documents 2 and 3 propose providing 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 ceramic is not laminated, a part of the shielding layer can have a high visible light transmittance area (transparent 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.

Japanese Patent Application Publication No. 2000-077173 Japanese Patent Application Publication No. 2006-327381 JP2007-039278A

Because the transparent window is also part of the windshield, it, along with other areas, can become foggy or frozen. Therefore, it is conceivable to arrange a heating wire as described above also in the transmission window to remove fogging and/or ice. However, the inventors of the present invention have found that the following problems arise when the bus bars and heating wires are arranged in the conventional manner.

The problems discovered by the inventors of the present invention will be explained using FIGS. 1 and 2. FIG. 1 schematically illustrates a windshield 100 according to a conventional example. Moreover, FIG. 2 schematically illustrates the configuration of the bus bar section 104 and the heating wire 105 according to a conventional example. As illustrated in FIG. 1, in a conventional windshield 100, a shielding layer 101 is provided along the periphery.

This shielding layer 101 may be provided with a protruding area 102 that protrudes inward in the surface direction from a portion along the upper edge of the windshield 100, and a camera may be placed inside the vehicle so as to be hidden in this protruding area 102. In this case, the above-described transparent window 103 is provided in the protrusion area 102 so that the camera can photograph the situation outside the vehicle.

At this time, if the heating section that heats the transmission window 103 is constructed as in the conventional example illustrated in Patent Document 1, the bus bar section 104 and the heating section 105 that constitute the heating section are arranged as illustrated in FIG. will be placed in That is, the pair of busbar sections 104 are arranged on both sides of the transmission window 103, and the plurality of heating wires 105 are arranged so as to pass through the transmission window 103 and be connected to both busbar sections 104 in parallel.

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

One aspect of 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 a shielding layer.

The present invention adopts the following configuration in order to solve the above-mentioned problems.

That is, a windshield according to one aspect of the present invention is an automobile windshield in which an information acquisition device that acquires information from outside the vehicle by irradiating and/or receiving light can be arranged, the information acquisition device a glass plate having an information acquisition area facing the light through which the light passes; a shielding layer provided on the glass plate to block a view from outside the vehicle; a pair of bus bar portions and a plurality of heating wires; An information acquisition area heating section that heats the acquisition area. The shielding layer includes a strip-shaped region extending along an edge of the glass plate, and the information acquisition region is arranged adjacent to the inner side of the strip-shaped region in the plane direction, and the information acquisition region is arranged on both sides of the information acquisition region heating section. The busbar parts are arranged side by side so as to be included in the band-shaped region in the viewing direction, and each heating wire of the information acquisition area heating part is connected in parallel to both the busbar parts, and from one busbar part in a planar direction. It extends inward, passes over the information acquisition area, is turned back, and extends toward the other bus bar section.

In the windshield according to this configuration, an information acquisition area for the information acquisition device to acquire information outside the vehicle is arranged adjacent to the inside of the band-shaped area of the shielding layer in the surface direction, and the information acquisition area heats the information acquisition area. Both busbar portions constituting the heating portion are arranged side by side in the band-shaped region. As a result, since both busbar portions are hidden in the band-shaped region, there is no need 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.

Moreover, as another form of the windshield according to the above configuration, among the plurality of heating wires, the heating wire extending further inward in the plane direction may have a larger cross-sectional area. For 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 (1) described below. Therefore, if all the heating wires have the same cross-sectional area, the heating wires extending further outward in the surface direction will generate less heat, and it may not be possible to evenly heat the entire information acquisition area. As a result, there is a possibility that cloudiness and/or ice may remain partially in the information acquisition area, or there may be a portion where the removal of cloudiness and/or ice is slow. On the other hand, according to this configuration, by increasing the cross-sectional area of the heating wire that extends further inward in the surface direction, there is a difference in the amount of heat generated between the heating wire that extends further 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 heated evenly, thereby making it possible to appropriately remove fogging and/or ice from the information acquisition area. Note that when the thickness of each heating wire is approximately constant, the cross-sectional area of each heating wire is proportional to the line width (which may also be referred to as "wire diameter") of each heating wire. 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 of the plurality of adjacent heating wires may have a portion extending in parallel with each other, and the heating wires adjacent to each other may have portions extending in parallel to each other. The parallel extending portions may each be formed in a wave-like manner. When adjacent heating wires have portions that extend parallel to each other, and the parallel extending portions of the adjacent heating wires are formed in a straight line, the light is scattered in one direction due to the diffraction of light that occurs at the edges of these portions. A reinforcing interaction occurs. As a result, a linear pattern with high light intensity is generated, which may adversely affect information acquisition by the information acquisition device. On the other hand, by forming the parallel-extending portions of adjacent heating wires into a wavy shape, it is possible to disperse the directions in which light is strengthened in multiple directions, weakening the light intensity of the pattern that occurs in each direction. be able to. Therefore, according to the configuration, it is possible to prevent light diffraction from occurring in the plurality of heating wires, which has an adverse effect on information acquisition by the information acquisition device.

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

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

Moreover, as another form of the windshield according to the above structure, the plurality of heating wires may be formed of copper. Copper is an easy material to work with. Further, since copper is chemically stable, it can be processed using chemical processing methods. Furthermore, copper is a cheaper material than silver and the like. Therefore, by using copper for each heating wire, manufacturing costs can be reduced. Furthermore, by manufacturing the busbar portion with copper, it is possible to prevent abnormal heat generation due to contact resistance that occurs when electricity is passed across different materials.

Further, as another form of the windshield according to the above configuration, the windshield may further include an other area heating section that has one or more heating wires and heats an area other than the information acquisition area. According to this configuration, it becomes possible to remove fogging and/or ice from areas other than the information acquisition area as well.

Moreover, 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 heating may be different between the information acquisition area and other areas. For example, suppose that 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 do not need to be heated with the same amount of heat. According to this configuration, such a request can be met 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 to be different from each other. can.

Note that 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 region heating section can be made larger than that of the other region heating section. On the other hand, the cross-sectional area of each heating wire of the information acquisition area heating section may be smaller 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 region heating section can be made smaller than that of the other region 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 section. 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 in FIG. FIG. 6 schematically illustrates a cross section taken along line BB in FIG. 3. FIG. 7 schematically illustrates a manufacturing process of a laminated glass according to an embodiment. FIG. 8 is a partially enlarged view schematically illustrating the information acquisition area heating section of the windshield according to the embodiment. FIG. 9 shows an example in which straight wires are arranged in parallel. Figure 10 shows the pattern that occurs when light is passed through straight wires arranged in parallel. FIG. 11 shows an example in which wavy (sinusoidal) wires are arranged in parallel. Figure 12 shows the pattern that occurs when light is passed through wavy wires arranged in parallel. FIG. 13 schematically illustrates an information acquisition area heating unit according to another embodiment. FIG. 14 schematically illustrates an information acquisition area heating unit according to another embodiment. FIG. 15 is a cross-sectional view schematically showing an example of a transfer sheet. FIG. 16A schematically illustrates a process of transferring each heating portion to laminated glass using a transfer sheet. FIG. 16B schematically illustrates a process of transferring each heating portion to laminated glass using a transfer sheet. FIG. 16C schematically illustrates a 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 embodiment. FIG. 21 schematically illustrates an information acquisition area heating unit according to another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment (hereinafter also referred to as "this embodiment") according to one aspect of the present invention will be described below based on the drawings. However, this embodiment described below is merely an illustration of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the invention. That is, in implementing the present invention, specific configurations depending on the embodiments may be adopted as appropriate. Note that in the following description, for convenience of explanation, the description will be made based on the orientation in the drawings.

§1 Configuration Example First, the windshield 1 according to the present embodiment will be described using FIGS. 3 to 6. 3 and 4 are a front view and a cross-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 in 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 disposed on the outside of the vehicle and an inner glass plate 22 disposed on the inner side of the vehicle are joined by an intermediate layer 4. We are prepared. This laminated glass 2 corresponds to the "glass plate" of the present invention. Further, a shielding layer 3 is provided along the peripheral edge of the laminated glass 2 to shield the view from outside the vehicle.

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

Furthermore, in this embodiment, an information acquisition area heating section 5 that heats the information acquisition area 23 and an other area heating section 6 that heats an area other than the information acquisition area 23 are provided in the intermediate layer 4. Cutouts 223 to 226 are provided in the inner glass plate 22 so that terminals can be connected to the respective heating parts (5, 6). This makes it possible to remove fog and/or ice from the information acquisition area 23 and other areas. Each component will be explained below.

[Outer glass plate and inner glass plate]
First, the outer glass plate 21 and the inner glass plate 22 will be explained. The outer 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.

Both glass plates (21, 22) have substantially the same shape as each other and are formed into a trapezoidal shape in plan view. Both glass plates (21, 22) may be curved in the direction perpendicular to the plane, 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 known glass plate can be used for each glass plate (21, 22). For example, each glass plate (21, 22) may be made of heat-absorbing glass, clear glass, green glass, UV green glass, or the like. However, each glass plate (21, 22) is configured to achieve visible light transmittance in accordance with the safety standards of the country in which the automobile is used. For example, each glass plate (21, 22) may be configured so that the transmittance of visible light (380 nm to 780 nm) is 70% or more, as defined by JIS R 3211. Note that this transmittance can be measured by the spectrometry method specified in JIS Z 8722, as defined in JIS R 3212 (3.11 Visible Light Transmittance Test). Furthermore, for example, the outer glass plate 21 can ensure a desired solar absorption rate, and the inner glass plate 22 can adjust the visible light transmittance to meet safety standards. Below, as an example of the composition of glass that can constitute each glass plate (21, 22), an example of the composition of clear glass and an example of the composition of heat ray absorbing glass are shown.

(clear glass)
SiO ₂ :70-73% by mass
Al ₂ O ₃ :0.6-2.4% by mass
CaO: 7-12% by mass
MgO: 1.0 to 4.5% by mass
R ₂ O: 13 to 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 ray absorbing glass)
The composition of the heat ray absorbing glass is, for example, based on the composition of 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 The ratio of TiO ₂ is 0 to 2% by mass, the ratio of TiO ₂ is 0 to 0.5% by mass, and the glass framework components (mainly SiO ₂ and Al ₂ O ₃ ) are replaced with T-Fe ₂ O ₃ and CeO ₂ and TiO ₂ can be reduced by the increment of TiO 2 .

The thickness of the laminated glass 2 according to this embodiment is not particularly limited, but from the viewpoint of weight reduction, it is preferable that the total thickness of both glass plates (21, 22) is 2.5 mm to 10.6 mm. It is more preferably 2.6 mm to 3.8 mm, and particularly preferably 2.7 mm to 3.2 mm. In this way, in order to reduce the weight, the total thickness of both glass plates (21, 22) may 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 impact from flying objects such as pebbles. On the other hand, increasing the thickness of the outer glass plate 21 increases the weight, which is not preferable. From this viewpoint, 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 determined as appropriate depending on 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 can be made smaller than the thickness of the outer glass plate 21, for example, in order to reduce the weight of the laminated glass 2. . 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. It is particularly preferable that the thickness is 1.4 mm. Furthermore, the thickness of the inner glass plate 22 is preferably 0.8 mm to 1.3 mm. The thickness to be adopted for the inner glass plate 22 can be determined as appropriate depending on the embodiment.

[Shielding layer]
Next, the shielding layer 3 that shields the view from outside the vehicle will be explained. 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 to 6. This shielding layer 3 is laminated along the periphery of the fourth surface 222 of the inner glass plate 22 and blocks light from entering from the periphery 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 his companion sitting in the passenger seat of the car equipped with this windshield 1 can pass through this area. You will be able to check the outside of the vehicle in front of you. Therefore, the area where the shielding layer 3 is not provided is configured to have a visible light transmittance to the extent that at least the traffic situation outside the vehicle can be visually observed.

In this embodiment, a strip-shaped region 31 is provided approximately at the center of a portion along the upper edge of the laminated glass 2, and an information acquisition region 23 is provided below and adjacent to this strip-shaped region 31. As shown in FIG. 4, the photographing device 8 arranged on the inside of the vehicle relative to 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 visible light transmittance of 70% or more, for example, as defined in JIS R 3211, as described above.

Note that the dimensions of each part of the shielding layer 3 may be set as appropriate depending on the embodiment. For example, the width of the portion along each of the upper and lower edges of the laminated glass 2 may be set in a range of 20 mm to 100 mm. Further, the width of the portion along each of the left end side and right end side of the laminated glass 2 may be set in a range of 15 mm to 70 mm.

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

*1, Manufactured by Asahi Chemical Industries, Ltd.: Black 6350 (Pigment Green 17)
*2, Main ingredients: Bismuth borosilicate, zinc borosilicate

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

Furthermore, in FIG. 3, the strip area 31 and the information acquisition area 23 are slightly apart. "The information acquisition area is arranged adjacent to the inner side of the strip area in the plane direction" does not require that the information acquisition area and the strip area are connected to each other, and may also include a state in which they are slightly separated like this.

[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) that sandwich the heat generating layer. Each layer will be explained below.

<Heating layer>
First, the heat generating layer will be explained. The heat generating layer includes a sheet-like base material 41, and an information acquisition area heating section 5 and another area heating section 6 arranged on the base material 41. The shape of the base material 41 may be the same as each glass plate (21, 22) described above, or may be smaller than each glass plate (21, 22).

(Information acquisition area heating section)
The information acquisition area heating unit 5 is configured to heat the information acquisition area 23 set on the laminated glass 2 and 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 is connected in parallel to a pair of busbar sections 51 disposed on the base material 41 and both busbar sections 51. It is equipped with three heating wires 52A to 52C. In addition, below, for convenience of explanation, these are also called 52 A of 1st heating wires, 2nd heating wire 52B, and 52 C of 3rd heating wires.

As shown in each figure, both busbar parts 51 are arranged so as to be included in the band-shaped region 31 of the shielding layer 3 in the viewing direction. The visual field is the visual field of the driver and his companion sitting in the passenger seat when the windshield 1 is attached to a car, and for example, in the direction perpendicular to the page of FIG. ) is perpendicular to the plane). In addition, as shown in FIG. 3, both busbar portions 51 are arranged side by side in the direction in which the band-shaped region 31 extends, that is, in the left-right direction. Further, both busbar portions 51 are arranged inward in the plane direction from each notch (223, 224) so as not to be exposed from each notch (223, 224) formed on the upper end side of the inner glass plate 22. There is. Each of the heating wires 52A to 52C extends inward in the plane direction (ie, downward) from one busbar section 51, passes over the information acquisition area 23, is turned back, and is connected to the other busbar section 51.

In this embodiment, as an example of the shape, each of the heating wires 52A to 52C is formed in a substantially U-shape. That is, each of the heating wires 52A to 52C includes a pair of side portions that face each other in the left-right direction and extend in the vertical direction, and a lower end portion that extends in the left-right direction so as to connect the lower ends of both side portions. .

The second heating wire 52B is arranged outside the third heating wire 52C, and extends from each bus bar portion 51 to the inner side 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 further inward in the plane direction from each bus bar 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, and more preferably 5 μm to 15 μm. Further, according to this, the cross-sectional area of each heating wire 52A to 52C can be, for example, 1 μm ² to 250,000 μm ² , preferably 25 μm ² to 10,000 μm ² , and preferably 25 μm ² to 225 μm ² . is even more preferable. 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. Note that there may be variations in cross-sectional area within each of the heating wires 52A to 52C. In this case, the cross-sectional area measurement location may be set at the center of each of the heating wires 52A to 52C. Further, the cross-sectional area of each of the heating wires 52A to 52C may be the same. However, the following relational expressions 1 to 3 are known regarding the amount of heat generated by each of the heating wires 52A to 52C.

Note that V is voltage (potential difference), I is current, R is resistance, ρ is electrical resistivity, L is the length of the conductor, A is the cross-sectional area of the conductor, and W is the amount of heat generated (power consumption). Here, since the voltage of an automobile is generally constant, the value of V shown in Equations 1 to 3 above may be assumed to be constant. Similarly, since the electrical resistivity ρ is determined by the material, the values of ρ shown in Equations 1 to 3 above may also be assumed to be constant, assuming that the heating wires 52A to 52C are made of the same material. . Further, assuming that 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 determined by the product of the thickness and the line width. In addition, assuming that the thickness of each heating wire 52A-52C is approximately constant, the cross-sectional area of each heating wire 52A-52C is proportional to the line width. Therefore, when the thickness is approximately 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 approximately constant, the cross-sectional area of each heating wire 52A-52C is assumed to be proportional to its line width, and the cross-sectional area of each heating wire 52A-52C is defined as its line width. It may be changed by adjusting. However, the cross-sectional shape of each of the heating wires 52A to 52C is not limited to a rectangular shape, but 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 amount of heat generated (W) by the heating wire. Therefore, if the cross-sectional area of each of the heating wires 52A to 52C is made the same, the heating wire that extends further inward in the plane direction from both bus bar portions 51 will have a smaller amount of heat generated by that heating wire.

That is, the calorific value of the second heating wire 52B becomes smaller than that of the third heating wire 52C, and the calorific value of the first heating wire 52A becomes smaller than that of the second heating wire 52B. This may make it impossible to evenly heat the entire information acquisition area 23. Particularly, within this information acquisition region 23, the amount of heat generated is small in a portion away from both busbar portions 51, and there is a possibility that the removal of fogging 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 heating wire may have a larger cross-sectional area as it extends farther inward in the plane 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. This makes it possible to suppress the difference in the amount of heat generated between the heating wires 52A to 52C, and to evenly heat the information acquisition area 23.

However, depending on the arrangement and shape of each heating wire 52A to 52C, even if the cross-sectional area of each heating wire 52A to 52C is adjusted, the entire information acquisition region 23 may not be evenly heated. Therefore, it is better 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 heated evenly. preferable.

Note that the dimensions of each bus bar section 51, the interval between both bus bar sections 51, and the interval between each heating wire 52A to 52C may be set as appropriate depending on the embodiment. However, if both busbar parts 51 and each heating wire 52A to 52C have approximately the same thickness, if the width of each busbar part 51 becomes smaller than 10 times the line width of each heating wire 52A to 52C (for example, each If the width of each bus bar portion 51 is smaller than 5 mm when the line width of heating wires 52A to 52C is 500 μm, there is a risk that each bus bar portion 51 itself may generate abnormal heat. As a result, the heat generation efficiency of the information acquisition area heating section 5 may be reduced. Furthermore, if the dimensions of each bus bar section 51 are too small, there is a possibility that it will be difficult to connect the connection terminals (anode terminal or cathode terminal: not shown) provided on each bus bar section 51. On the other hand, if the dimensions of each bus bar section 51 are too large, each bus bar section 51 may protrude from the shielding layer 3 and obstruct the field of view. From these viewpoints, the dimensions of each bus bar section 51 may be set to, for example, 5 mm (horizontal) x 5 mm (vertical) to 60 mm (horizontal) x 60 mm (vertical). Further, the distance between both bus bar parts 51, that is, the distance between the centers of each bus bar part 51 in the horizontal direction, may be 10 mm to 120 mm. Further, for example, the interval between the portions of the heating wires 52A to 52C extending in the left-right direction may be 1 mm to 50 mm in the vertical direction, and preferably 10 mm to 50 mm. Further, for example, the distance between the vertically extending portions of the heating wires 52A to 52C may be 5 mm to 40 mm in the left-right direction, and preferably 10 mm to 40 mm.

Furthermore, in this embodiment, as shown in FIGS. 3 and 5, a connecting member 71 is used to supply electricity to each of the bus bar sections 51 and each of the heating wires 52A to 52C. That is, the connection material 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 of a conductive material, for example.

As shown in FIG. 5, each connecting member 71 is formed in a rectangular shape and is sandwiched between each bus bar portion 51 and the adhesive layer 43. Each connecting member 71 is fixed to each bus bar portion 51 by a fixing member 72 such as solder. For example, it is preferable to use a low melting point solder of 150° C. or lower for the fixing material 72 so that it can be fixed at the same time in an autoclave when assembling the windshield, which will be described later.

Further, each connecting member 71 extends from each bus bar portion 51 to the upper edge of the outer glass plate 21 and is exposed through each notch (223, 224) formed at the upper edge of the inner glass plate 22. . Then, by connecting the connection terminals of the cables extending from the car's power supply in this exposed part with a fixing material such as solder, electricity is passed from the power supply to each of the heating wires 52A to 52C via each bus bar part 51 to heat them. You will be able to do this.

In this way, each connecting member 71 fixes the connecting terminal to the portion exposed from each notch (223, 224) of the inner glass plate 22 without protruding from the ends of both glass plates (21, 22). It is now possible to do so. Note that each connecting member 71 may be formed of a thin material, and in that case, after being bent, the end portion can be fixed to each bus bar portion 51 with a fixing member 72.

(Other area heating section)
On the other hand, the other area heating unit 6 heats areas other than the information acquisition area 23 of the laminated glass 2, particularly the visual field area (area that comes into the field of view) of the driver and a companion sitting in the passenger seat, and heats the area other than the information acquisition area 23 of the laminated glass 2. This is a configuration for removing fog and/or ice in this area other than the above. Specifically, as illustrated in FIGS. 3 to 6, the other area heating section 6 extends in the left-right direction with a pair of busbar sections 61 disposed on the base material 41, and is connected to both busbar sections 61. It includes a plurality of heating wires 62 connected in parallel. In addition, in FIG. 3, the number of heating wires 62 is six. However, the number of heating wires 62 does not need to be limited to such an example, and may be appropriately selected depending on 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 bus bar portion 61 is formed to extend along the left and right edges. Each bus bar portion 61 is arranged inward in the plane direction from each notch (225, 226) so as not to be exposed from the notch (225, 226) formed on each of the left and right edges of the inner glass plate 22. There is. Moreover, each bus bar part 61 is arranged so as to be included in a portion along each of the left and right edges of the shielding layer 3 in the viewing direction.

The dimensions of each bus bar portion 61 may be set as appropriate depending on the embodiment. However, if each busbar part 61 and the heating wire 62 have the same thickness, and the width of each busbar part 61 becomes smaller than 10 times the line width of the heating wire 62 (for example, the line width of the heating wire 62 If the width of each bus bar portion 61 is smaller than 5 mm (500 μm), there is a risk that each bus bar portion 61 itself may generate abnormal heat. As a result, the heat generation efficiency of the other area heating section 6 may be reduced. On the other hand, if the width of each busbar part 61 is larger than 50 mm, each busbar part 61 may protrude from the shielding layer 3 and obstruct the field of view. Therefore, it is preferable that the width of each bus bar portion 61 is, for example, 5 mm to 50 mm. In order to suppress the heat generation of each bus bar part 61 itself, it is preferable that the width of each bus bar part 61 is smaller than ten times the line width of the heating wire 62. Note that each bus bar portion 61 does not need to be formed exactly along the base material 41. That is, each bus bar portion 61 does not need to 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 generally parallel to the vertical direction. The line width and interval of each heating line 62 may be set as appropriate depending on the embodiment. For example, a driver riding in a car equipped with the windshield 1 and a companion sitting in the passenger seat check the situation outside the car through the area where each heating wire 62 is provided. From this viewpoint, the line width of each heating line 62 is preferably 3 μm to 20 μm, more preferably 5 μm to 13 μm, and particularly preferably 8 μm to 10 μm. Further, 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.

Note that 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 viewing area of the driver and a companion sitting in the passenger seat, whereas the information acquisition area heating unit 5 warms the area (information acquisition area) that falls within the field of view of the photographing device 8. . Therefore, the heating ranges of the respective heating parts (5, 6) are largely different, and the purposes 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, assume that the information acquisition area 23 is heated to remove fogging, and the other areas are heated to remove ice. In such a case, it is preferable to set the amount of heat generated per unit area of the other area heating unit 6 to be larger than that of the information acquisition area heating unit 5. In this way, 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 relational expressions 1 to 3 above, by changing the cross-sectional area of each heating wire (52A to 52C, 62), the amount of heat generated by each heating wire (52A to 52C, 62) can be easily adjusted. For example, the cross-sectional area of each of the heating wires 52A to 52C of the information acquisition area heating section 5 may be made larger than each of the heating wires 62 of the other area heating section 6. 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 area of each of the heating wires 52A to 52C of the information acquisition area heating section 5 may be smaller than each of the heating wires 62 of the other area heating section 6. Thereby, 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. Note that 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. .

In addition, in this embodiment, as shown in FIGS. 3 and 6, in order to energize each bus bar section 61 and each heating wire 62 similarly to the information acquisition area heating section 5, connecting material 73 and fixing material 74 is used. The connecting member 73 corresponds to the connecting member 71 described above, and the fixing member 74 for fixing the connecting member 71 to each bus bar portion 61 corresponds to the fixing member 72 described above.

That is, each connecting member 73 is connected to each bus bar portion 61 by a fixing member 74, and then inserted into each notch (225, 225, 226), the connecting terminal can be fixed to the exposed part. By connecting the connection terminals of the cables extending from the car's power supply to these exposed parts using a fixing material such as solder, electricity can be applied to each heating wire 62 through each bus bar section 61 and heated. become.

Note that if the heating wire is not used to perform anti-fogging and/or de-icing in areas other than the information acquisition area 23, the area heating unit 6 may be omitted.

(material)
Next, the material of the heat generating layer will be explained. The base material 41 may be any transparent film, and its material does not need to be 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.

Moreover, each bus bar part (51, 61) and each heating wire (52A to 52C, 62) of each heating part (5, 6) are made of copper (or copper plated with tin, etc.), tungsten, etc. , silver, gold, aluminum, and alloys thereof. Here, each bus bar part (51, 61) and each heating wire (52A to 52C, 62) may be formed of the same material or different materials. However, copper is an easy material to work with. Further, since copper is chemically stable, it can be processed using chemical processing methods. Furthermore, copper is a cheaper material than silver and the like. Therefore, from the viewpoint of manufacturing cost, it is preferable to use copper as the material for each heating part (5, 6). Moreover, by manufacturing each bus bar part (51, 61) with copper, it is possible to prevent abnormal heat generation due to contact resistance that occurs when electricity is applied across different materials.

In addition, when each busbar part (51, 61) is formed of copper, since the shielding layer 3 is formed on the fourth surface 222 in this embodiment, each busbar part (51, 61) is made of copper. Therefore, each bus bar portion (51, 61) becomes visible from outside the vehicle. As a result, the appearance of the windshield 1 may become poor.

Therefore, when each bus bar part (51, 61) is formed of copper, the surface of each bus bar part (51, 61) on the outside of the vehicle, in other words, the surface that contacts the base material 41, is plated with black color. It is preferable to process it into Thereby, even if the shielding layer 3 is formed on the fourth surface 222, each bus bar part (51, 61) can be made difficult to see from the outside of the vehicle.

Next, a method for forming each bus bar portion (51, 61) and each heating wire (52A to 52C, 62) will be described. Each bus bar part (51, 61) and each heating wire (52A to 52C, 62) can be formed by placing a preformed thin wire (wire, etc.) on the base material 41.

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

At this time, each bus bar portion 51 and each heating wire 52A to 52C can be formed separately, or they can be formed integrally. Similarly, each bus bar portion 61 and each heating wire 62 can be formed separately, or they can be formed integrally. Note that "integral" means that there are no breaks (seamless) between materials and no interfaces exist.

Further, when forming a pattern on the base material 41 by etching, for example, each bus bar part (51, 61) of each heating part (5, 6) and each heating wire (52A to 52A) are formed in the following manner. 52C, 62) can be formed. First, metal foil is dry laminated on the base material 41 via a primer layer. For example, copper can be used as the metal foil. Then, by performing a chemical etching process using photolithography on the metal foil, each bus bar part (51, 61) of each heating part (5, 6) and each heating wire ( 52A to 52C, 62) can be integrally patterned.

In particular, when the line width of each heating wire (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, etc., and then each bus bar part (51, 61) and each heating wire (52A to 52C, 62) are formed by photolithography. Patterning may also be performed by

<Adhesive layer>
Next, each adhesive layer (42, 43) will be explained. Both adhesive layers (42, 43) are sheet-like members for sandwiching the heat generating layer and adhering 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 a cutout of the same shape at a position corresponding to each of the cutouts 223 to 226 of the inner glass plate 22. are doing.

The material of each adhesive layer (42, 43) may be selected as appropriate depending on the embodiment. For example, polyvinyl butyral resin (PVB), ethylene vinyl acetate (EVA), etc. can be used as the material for each adhesive layer (42, 43). In particular, polyvinyl butyral resin is preferable because it has excellent adhesiveness with each glass plate (21, 22) and also has excellent penetration resistance. Note that 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 adhesive strength.

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

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, 0.1 mm to 1.0 mm. It is more preferable that Note that in order to improve the adhesion between the adhesive layer 43 and the base material 41 arranged on the inner glass plate 22 side, each bus bar part (51, 61) and each heating wire (52A to 52C, 62 ) can be 1 μm to 500 μm, preferably 5 μm to 100 μm, and more preferably 5 μm to 15 μm.

The thickness of the heat generating 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 using a microscope (for example, VH-5500 manufactured by Keyence Corporation). Then, the thickness of the heat generating layer and each adhesive layer (42, 43) is visually identified and measured. At this time, in order to eliminate visual variations, the number of measurements was made five times, and the average value was taken as the thickness of the heat generating layer and each adhesive layer (42, 43).

Note that the thickness of the heat generating layer and each adhesive layer (42, 43) of the intermediate layer 4 may not be constant over the entire surface, and may be wedge-shaped, for example, for laminated glass used in a head-up display. In this case, the thickness of the heat generating 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. When the intermediate layer 4 is wedge-shaped, the outer glass plate 21 and the inner glass plate 22 are arranged at an angle to each other. Both glass plates (21, 22) of the laminated glass 2 may not be arranged parallel to each other, but may be arranged at an angle to each other in this manner. For example, an intermediate layer 4 using a heat generating layer and adhesive layers (42, 43) whose thickness increases at a rate of change of 3 mm or less per meter may be used.

[Photography equipment]
Next, the photographing device 8 will be explained. 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. The image acquired by the photographing device 8 is sent to an 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 section, a control section, an input/output section, etc. so that it can perform such image analysis and present the results to the user (driver). Such an image processing device 81 may be a general-purpose device such as a PC (Personal Computer) or a tablet terminal, in addition to a device designed specifically for the provided service.

§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 explained in order. Note that the method for manufacturing the windshield 1 described below is only an example, and each step may be changed as much as possible. Further, regarding the manufacturing process described below, steps may be omitted, replaced, or added as appropriate depending on the embodiment.

First, a method for manufacturing the laminated glass 2 will be described using FIG. 7. FIG. 7 illustrates a production line for laminated glass 2. As illustrated in FIG. 7, in order to bend and form the laminated glass 2, the production line for the laminated glass 2 includes a ring-shaped mold 200, a conveyor table 201 for transporting the mold 200, and a heating furnace 202. and a slow cooling furnace 203.

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

Next, the ceramic printed in each area is dried appropriately. After drying the ceramic, a flat laminated glass 20 is formed by stacking the outer glass plate 21 and the inner glass plate 22 vertically so that the second surface 212 and the third surface 221 face each other, The formed flat laminated glass 20 is placed on a mold 200. The mold 200 is placed on a conveyor table 201, and with the laminated glass 20 placed on the mold 200, the conveyor table 201 sequentially passes through a heating furnace 202 and a slow cooling furnace 203.

When heated in the heating furnace 202 to around the softening point temperature, both glass plates (21, 22) are curved downward from the periphery due to their own weight, and are formed into a curved shape. Subsequently, both glass plates (21, 22) are carried from the heating furnace 202 to the slow cooling furnace 203, where a slow cooling process is performed. Thereafter, both glass plates (21, 22) are carried out from the lehr 203 and left to cool.

After both glass plates (21, 22) are formed in this way, the intermediate layer 4 is sandwiched between both 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 heat generating 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 on the inner side of each of the notches 223 to 226 of the inner glass plate 22 in the plane direction. Furthermore, the notches of each adhesive layer (42, 43) are made to coincide with each of the notches 223 to 226 of the inner glass plate 22. As a result, the outer glass plate 21 is exposed from each of the cutouts 223 to 226 of the inner glass plate 22.

Subsequently, each connecting material (71, 73) is inserted between the heat generating layer and the adhesive layer 43 from each of the notches 223 to 226. At this time, each connecting material (71, 73) is coated with low melting point solder as each fixing material (72, 74), and this solder is placed on each bus bar part (51, 61). do it like this.

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

Next, main adhesion is performed. The pre-bonded laminate is subjected to main bonding in an autoclave, for example, at 8 to 15 atm and at 100 to 150°C. Specifically, the main bonding can be performed under conditions of, for example, 14 atm and 135°C. Through the above preliminary adhesion and main adhesion, each adhesive layer (42, 43) is adhered to each glass plate (21, 22) with the heating layer sandwiched therebetween. Moreover, the solder of each connecting material (71, 73) is melted, and each connecting material (71, 73) is fixed to each bus bar part (51, 61). Thereby, the windshield 1 according to this embodiment is manufactured.

The windshield 1 manufactured as described above is attached to a vehicle body, and at that time, connection terminals are fixed to each connection member (71, 73). Thereafter, when each connection terminal is energized, electricity flows to each heating wire (52A to 52C, 62) via each connection member (71, 73) and each bus bar portion (51, 61), and heat is generated. Thereby, fogging and/or ice in the information acquisition area 23 and other areas can be removed.

<Features>
As described above, in the windshield 1 according to the present embodiment, the information acquisition region 23 is arranged adjacently below (on the inside in the surface direction) the strip region 31 of the shielding layer 3 along the upper edge of the laminated glass 2. , a photographing device 8 is installed inside the vehicle. The busbar parts 51 of the information acquisition area heating unit 5 for removing cloudiness and/or ice from the information acquisition area 23 are arranged side by side in the horizontal direction within the strip area 31 adjacent above the information acquisition area 23. be done. As a result, both busbar portions 51 are hidden by the band-shaped region 31, so it is not necessary to provide the shielding layer 3 in the area around the information acquisition area 23 except for the upper part of the information acquisition area 23. That is, instead of arranging the busbar sections 51 so as to sandwich the information acquisition area 23, in this embodiment, both the busbar sections 51 are arranged in an area in one direction from the information acquisition area 23. The shielding layer 3 may be provided in the region in the direction of , or may not be provided. 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 above, the above descriptions are merely illustrative of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the invention. For example, regarding each component of the windshield 1, components may be omitted, replaced, or added as appropriate depending on the embodiment. Further, the shape and size of each component of the windshield 1 may be determined as appropriate depending on the embodiment. For example, the following changes are possible. In addition, below, the same code|symbol is used regarding the same component as the said embodiment, and description was abbreviate|omitted suitably.

<3.1>
For example, in the shielding layer 3 according to the embodiment described above, the band-shaped area 31 is set along the upper edge of the laminated glass 2, and the pair of busbar parts 51 are arranged side by side in the left-right direction so as to be included in the area. There is. However, the position where the strip area 31 is set does not need to be limited to this example, and may be appropriately selected depending on the embodiment.

For example, the band-shaped region 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 placed inside the strip area 31 in the plane direction. For example, when the strip area 31 is set along the lower edge of the laminated glass 2, the information acquisition area 23 can be placed above and adjacent to the strip area 31.

Here, in the above-mentioned FIG. 3, the band-shaped region 31 is formed in a rectangular shape extending in the left-right direction. However, this band-shaped region 31 is a region for shielding the pair of busbar portions 51 arranged side by side, and only needs to extend in at least one direction. Therefore, the shape of the strip area 31 does not have to be rectangular and may be selected as appropriate depending on the embodiment.

Further, for example, in the embodiment described above, the information acquisition area heating section 5 has three heating wires 52A to 52C. However, the number of heating wires provided in the information acquisition area heating section 5 does not need to be limited to three, and may be two, or four or more. The number of heating wires included in the information acquisition area heating section 5 may be selected as appropriate depending on the embodiment. Each heating wire is connected to the busbar section 51 in parallel. In this way, since the information acquisition area heating unit 5 includes a plurality of heating wires, even if any heating wire is broken, the information acquisition area 23 can be heated by the other heating wires.

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

That is, light diffraction occurs at the ends of each of the heating wires 52A to 52C. This may cause the lights to strengthen or weaken each other 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 ends of each wire. The conditions for each wire and light source are as follows.

(Wire conditions)
・Line width: 10μm
・Pitch (distance between adjacent wires): 2mm
(Light source conditions)
・Light source type: 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 pattern of striations with strong light intensity in one direction is generated. In other words, it has been found that the existence of the portions 522A to 522C as described above may easily affect the image taking by the image capturing device 8.

Therefore, as shown in FIG. 11, an experiment similar to the above was conducted using a wire having a wave shape such as a sine wave (angle: θ). Note that the wire conditions (line width, pitch) and light source conditions (type of light source, arrangement) were the same as above. θ represents the angle between the tangent at the inflection point (center of amplitude) of the heating line and the horizontal line.

FIG. 12 shows the results of the experiment. As shown in FIG. 12, it has been found that when the wires are made wavy, although light diffraction occurs at the ends of each wire, the directions in which the light intensifies can be dispersed in multiple directions. That is, it has been 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 will adversely affect the photographing by the photographing device 8.

Therefore, when at least one of the adjacent heating wires 52A to 52C has a portion extending parallel to each other, the parallel extending portions of the adjacent heating wires may each 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. Each of the heating wires 53A to 53C is configured in the same manner as each of the heating wires 52A to 52C according to the embodiment described above, except that the heating wires 53A to 53C are formed in a wavy shape. Here, in the modification shown in FIG. 13, the adjacent first heating wire 53A and second heating wire 53B extend in 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 sinusoidal pattern. Furthermore, the adjacent second heating wire 53B and third heating wire 53C extend in 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. Thereby, as shown in FIG. 12, it is possible to reduce the possibility that the photographing by the photographing device 8 will be adversely affected by the diffraction of light generated at the ends of each heating wire.

Further, as illustrated in FIG. 14, the wavy patterns of parallelly extending portions of adjacent heating wires may be shifted from each other. FIG. 14 shows an example in which the sinusoidal patterns of the heating wires 53A to 53C are shifted. By shifting the wavy patterns of the parallel extending portions of adjacent heating wires from each other in this manner, it is possible to further prevent the formation of a striated pattern with high light intensity as shown in FIG. 10. Thereby, it is possible to further reduce the possibility that the photographing by the photographing device 8 will be adversely affected by the diffraction of light occurring at the ends of each heating wire.

In addition, if a striation pattern with high light intensity as described above occurs, edges of the striation pattern will occur in the image captured using the light incident on the photographing device 8, for example. , errors are more likely to occur in image processing such as pattern recognition. On the other hand, by making each heating wire wavy as described above, the light passing between the heating wires can be flattened, so the image captured using the light incident on the photographing device 8 It is possible to suppress the occurrence of edges of the filament pattern within the area. Thereby, it is possible to reduce the possibility that an error will occur when 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 extremely difficult to suppress the generation of linear patterns with high light intensity by making each heating wire wavy as described above. becomes important.

The same applies to each heating wire 62 of the other area heating section 6. Therefore, at least the portion of each heating wire 62 that extends in parallel with the 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 wire (53A to 53C, 62) in a wave shape, it is possible to prevent the generation of a linear pattern with strong light intensity due to the above-mentioned light diffraction, and also to The area where the lines (53A to 53C, 62) are arranged can be easily heated uniformly. Note that the shape of each heating wire (53A to 53C, 62) does not need to be limited to the above-mentioned straight or wavy shape, and may be appropriately selected depending on the embodiment.

<3.2>
Further, for example, in the embodiment described above, the information acquisition area heating unit 5 and the other area heating unit 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 does not need to 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.

Note that 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 forming the laminated glass 2, the information acquisition area heating unit 5 is printed on one of the surfaces (typically, the fourth surface 222) of the outer glass plate 21 and the inner glass plate 22 by screen printing or the like. and the pattern of the other area heating section 6 is printed. Then, by firing 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.

Also, by the transfer shown in FIGS. 15 and 16A to 16C, it is possible to arrange the information acquisition area heating section 5 and the other area heating section 6 on either surface of the outer glass plate 21 or the inner glass plate 22. can. FIG. 15 illustrates a transfer sheet used for transferring the information acquisition area heating section 5 and the other area heating section 6. As shown in FIG. Further, FIGS. 16A to 16C illustrate a 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 illustrated in FIG. 15 includes a release film 11, a pattern of an information acquisition area heating section 5 and another area heating section 6 formed by screen printing or the like on the release film 11, and a pattern arranged so as to cover the pattern. It has an adhesive layer 12. The release film 11 may be of a known type, and the information acquisition area heating section 5 and the other area heating section 6 are those described above. Further, for the adhesive layer 12, an adhesive made of resin such as acrylic, methylcellulose, nitrocellulose, ethylcellulose, vinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, or polyester can be used. Note that the adhesive layer 12 may be covered with a removable protective film or the like until the transfer.

Next, as shown in FIG. 16A, the adhesive layer 12 of this transfer sheet is attached to either surface of the laminated glass 2 after molding, and then 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. Thereafter, when this 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 onto 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. Note that the configuration of the transfer sheet does not need to be limited to the above example, and may be appropriately selected depending on the embodiment as long as the information acquisition area heating section 5 and the other area heating section 6 can be transferred. good.

As described above, forming the information acquisition area heating section 5 and the other area heating section 6 using transfer sheets 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 on the laminated glass 2 directly. Therefore, fabrication of highly structured patterns, fabrication of laminates, etc. becomes easy. Next, if such transfer sheets are produced in large quantities, the productivity when forming the information acquisition area heating section 5 and the other area heating section 6 on the laminated glass 2 will be improved. Furthermore, the information acquisition area heating section 5 and the other area heating section 6 can be attached to uneven surfaces as well.

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

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-fog film 9 is not particularly limited as long as it has an anti-fog effect on the laminated glass 2, and any known film can be used. In general, there are three types of antifogging films: a hydrophilic type that forms a film of water generated from water vapor on the surface, 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 anti-fog film 9.

Thereby, the information acquisition area 23 can be made more difficult to fog. Further, for example, in order to remove fogging in the information acquisition area 23 by the information acquisition area heating unit 5, it takes a certain amount of time for each of the heating wires 52A to 52C to be energized and heated. Therefore, if the information acquisition area 23 repeatedly becomes cloudy, the time loss required to remove the cloudiness increases accordingly. On the other hand, according to the modification, the information acquisition area 23 can be made relatively less foggy, so the number of times the information acquisition area heating unit 5 is used to remove fogging from the information acquisition area 23 can be reduced. This can reduce time loss by that much.

In this modification, the anti-fog film 9 is directly attached to the fourth surface 222 of the inner glass plate 22. However, the arrangement of the antifogging film 9 does not need to be limited to such an example, and may be appropriately selected depending on the embodiment. For example, the antifogging film 9 can be placed on a sheet-like base material, and then this base material can be attached to the laminated glass 2 with a transparent adhesive. Moreover, the adhesive, the base material, and the antifogging film 9 can also be laminated in this order. The base material 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 antifogging film 9 can be configured to include a water-repellent group and a metal oxide component, and preferably further include a water-absorbing resin. The antifogging film 9 may further contain other functional components as necessary. The water-absorbing resin may be of any type 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 (a metal compound containing a water-repellent group). The metal oxide component can be supplied to the antifogging film from water-repellent group-containing metal compounds, other metal compounds, metal oxide fine particles, and the like. Each component will be explained below.

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

Polyvinyl acetal can be obtained by acetalizing polyvinyl alcohol by subjecting aldehyde to a condensation reaction. 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 saponification of polyvinyl acetate. The degree of acetalization is preferably 2 to 40 mol%, more preferably 3 to 30 mol%, particularly 5 to 20 mol%, and in some cases 5 to 15 mol%. The degree of acetalization can be measured, for example, based on ¹³ C nuclear magnetic resonance spectroscopy. Polyvinyl acetal having a degree of acetalization within the above range is suitable for forming an antifogging film with good water absorption and water resistance.

The average degree of polymerization of polyvinyl alcohol is preferably 200 to 4,500, more preferably 500 to 4,500. A high average degree of polymerization is advantageous for forming an antifogging 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 film formation. be. The degree of saponification of polyvinyl alcohol is preferably 75 to 99.8 mol%.

Examples of the aldehyde to be subjected to the condensation reaction with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. Also, benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl group-substituted benzaldehydes; chlorobenzaldehyde, other halogen atom-substituted benzaldehydes; alkyl groups such as hydroxy groups, alkoxy groups, amino groups, cyano groups, etc. Examples include substituted benzaldehydes in which hydrogen atoms are substituted with functional groups other than groups; aromatic aldehydes such as fused aromatic ring aldehydes such as naphthaldehyde and anthraldehyde. Aromatic aldehydes with strong hydrophobicity are advantageous in forming an antifogging film with a low degree of acetalization and excellent water resistance. The use of aromatic aldehydes is also advantageous in forming a membrane with high water absorption while leaving a large amount of hydroxyl groups. Preferably, the polyvinyl acetal contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

The content of the water-absorbing 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 viewpoints of film hardness, water absorption, and antifogging properties. It is 95% by mass or less, more preferably 90% by mass or less, particularly preferably 85% by mass or less.

[Water repellent group]
Next, the water-repellent group will be explained. The water-repellent group makes it easy to achieve both strength and anti-fogging properties of the anti-fog film, and also makes the surface of the film hydrophobic, contributing to ensuring the straightness of incident light even if water droplets are formed. . In order to fully obtain the effect of the water-repellent group, it is preferable to use a water-repellent group with 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 alkyl group having 1 to 30 carbon atoms in which at least a portion of the hydrogen atoms are replaced with fluorine atoms. At least one type 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. An alkyl group having more than 30 carbon atoms may cause the antifogging film to become cloudy. From the viewpoint of balance between antifogging properties, strength and appearance of the film, the number of carbon atoms in the chain alkyl group is preferably 20 or less, for example 1 to 8, and for example 4 to 16, preferably 4 to 8. be. Particularly preferred alkyl groups are straight-chain alkyl groups having 4 to 8 carbon atoms, such as n-pentyl, n-hexyl, n-heptyl, and n-octyl. Regarding (2), the fluorine-substituted alkyl group may be a group in which only some of the hydrogen atoms of a chain or cyclic alkyl group are substituted with fluorine atoms, or all of the hydrogen atoms in a chain or cyclic alkyl group are substituted with fluorine atoms. It may also be a group in which is 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 becomes too large, it may separate from other components in the coating solution for forming a film.

(Hydrolyzable metal compound with water-repellent group)
In order to incorporate a water-repellent group into an antifogging film, a metal compound having a water-repellent group (a metal compound containing a water-repellent group), especially a metal compound having a water-repellent group and a hydrolyzable functional group or a halogen atom ( A hydrolyzable metal compound containing a water-repellent group) or a hydrolyzate thereof may be added to a coating liquid for forming a film. In other words, the water-repellent group may be derived from a hydrolyzable metal compound containing a water-repellent group. 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.
R _m SiY _4-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 some of the hydrogen atoms may be substituted with fluorine atoms, and Y is a hydrolyzable functional group. group or a halogen atom, and m is an integer of 1 to 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, and is preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. An alkenyloxy group is, for example, an isopropenoxy group. The halogen atom is preferably chlorine. Note that the functional groups exemplified here can also be used as "hydrolyzable functional groups" described below. m is preferably 1-2.

The compound represented by formula (I) provides a component represented by formula (II) below when hydrolysis and polycondensation proceed completely.
R _m SiO _(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 bonded to each other via oxygen atoms in the antifogging film.

As described above, the compound represented by formula (I) is hydrolyzed or partially hydrolyzed, and furthermore, at least a portion thereof is polycondensed, so that silicon atoms and oxygen atoms are alternately connected and three-dimensionally. Forms a network structure of expanding siloxane bonds (Si-O-Si). 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 in 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). To form an antifogging film using a silicon compound that does not have a water repellent group and has a hydrolyzable functional group or a halogen atom (hydrolyzable silicon compound that does not contain a water repellent group) together with a hydrolyzable silicon compound that contains a water repellent group. When added to a coating liquid, a network structure of siloxane bonds can be formed that includes silicon atoms bonded to water-repellent groups and silicon atoms not bonded to water-repellent groups. With such a structure, it becomes easy to adjust the water-repellent group content and the metal oxide component content in the antifogging film independently of each other.

When the anti-fog film contains a water-absorbing resin, the water-repellent group improves the anti-fog performance by improving water vapor permeability on the surface of the anti-fog film containing the water-absorbing resin. Since the two functions of water absorption and water repellency are contradictory to each other, water-absorbing materials and water-repellent materials have traditionally been added to separate layers, but the water-repellent group contained in the anti-fog film is Eliminates the uneven distribution of water near the surface of the fog layer, prolongs the time until dew condensation, and improves the anti-fog properties of the anti-fog film. The effect will be explained below.

Water vapor that has entered the antifogging film containing a water-absorbing resin forms hydrogen bonds with the hydroxyl groups of the water-absorbing resin and is retained in the form of bound water. As the amount increases, water vapor is retained in the form of bound water, semi-bound water, and finally 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 water-repellent groups reduce the rate of hydrogen bond formation. Therefore, in an antifogging film containing a water-repellent group, water will eventually be retained in the film in one of the above forms, but by the time it is retained, it remains as water vapor all the way to the bottom of the film. Can be spread. Furthermore, once retained water 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 water retained in the thickness direction of the membrane becomes relatively uniform from near the surface to the bottom of the membrane. In other words, the entire thickness of the antifogging film can be effectively utilized to absorb water supplied to the film surface, making it difficult for water droplets to condense on the surface, resulting in high antifogging properties.

On the other hand, in conventional antifogging films that do not contain water-repellent groups, water vapor that has entered the film is very easily retained in the form of bound water, semi-bound water, or free water. Therefore, the invading water vapor tends to be retained near the surface of the membrane. As a result, the water content in the membrane is extremely high near the surface and rapidly decreases toward the bottom of the membrane. In other words, although water can still be absorbed at the bottom of the membrane, the area near the surface of the membrane becomes saturated with moisture and condenses as water droplets, resulting in limited antifogging properties.

When a water-repellent group is introduced into an antifogging film using a hydrolyzable silicon compound containing a water-repellent group (see formula (I)), a strong network structure of siloxane bonds (Si--O--Si) 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 may be added in such an amount that the contact angle of water on the surface of the antifogging film is 70 degrees or more, preferably 80 degrees or more, more preferably 90 degrees or more. For the contact angle of water, a value measured by dropping a 4 mg water droplet onto the surface of the membrane is adopted. Particularly when using a methyl group or an ethyl group, which has a rather weak water repellency, as a water repellent group, it is preferable to incorporate the water repellent group into the antifogging film in an amount such that the contact angle of water falls within the above range. The upper limit of this water contact angle is not particularly limited, but is, for example, 150 degrees or less, 120 degrees or less, and further 105 degrees or less. It is preferable that the water-repellent group is uniformly contained in the anti-fog film so that the contact angle of the water is within the above range in all areas of the surface of the anti-fog film.

Here, the relationship between the contact angle of water and the antifogging film 9 will be explained using FIGS. 18 and 19. 18 and 19 show a state in which water droplets (90, 91) having different contact angles are attached to the antifogging film 9. As shown in FIGS. 18 and 19, the area covered by the water droplets (90, 91) formed by the condensation of the same amount of water vapor on the surface of the anti-fog film 9 is The larger the angle, the smaller the angle tends to be. Furthermore, the smaller the area covered by the water droplets (90, 91), the smaller the ratio of the area where light incident on the antifogging film 9 is scattered. Therefore, the antifogging film 9 in which the contact angle of water is increased due to the presence of the water-repellent group 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 above-mentioned preferred range. When containing a water-absorbing resin, the anti-fog film contains 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, based on 100 parts by mass of the water-absorbing resin. It is also preferable that the water-repellent group is contained in an amount of 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 an oxide component of Si (silica component). ). When containing a water absorbent resin, the antifogging 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 even more preferably 1 part by weight or more, particularly preferably 5 parts by weight or more, in some cases 7 parts by weight or more, if necessary 10 parts by weight or more, and 60 parts by weight or less, especially 50 parts by weight or less, preferably 40 parts by weight or less, The metal oxide component is preferably contained in an amount of 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 a necessary component to ensure the strength of the film, particularly the scratch resistance, but if its content is excessive, the antifogging properties of the film will be reduced.

At least a portion of the metal oxide component may be a metal oxide component derived from a hydrolyzable metal compound or a hydrolyzate thereof, which is added to the coating solution for forming the antifogging film. Here, the hydrolyzable metal compound is 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 metal compound having a water-repellent group. It is at least one selected from metal compounds having a hydrolyzable functional group or a halogen atom (hydrolyzable metal compounds not containing a water-repellent group). The metal oxide component derived from a) and/or b) is an oxide of metal atoms constituting the hydrolyzable metal compound. The metal oxide component is a metal oxide component derived from metal oxide fine particles added to a coating solution for forming an antifogging film, and a hydrolyzable metal compound or its components added to the coating solution. It may also contain a metal oxide component derived from a hydrolyzate. Here too, the hydrolyzable metal compound is at least one selected from a) and b) above. The above b), that is, the hydrolyzable metal compound having no water-repellent group, may contain at least one selected from tetraalkoxysilane and a silane coupling agent. The metal oxide fine particles and the above b) will be explained below, except for the above a) which has already been explained.

(Metal oxide fine particles)
The antifogging film 9 may further contain metal oxide fine particles as at least a 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, and is preferably silica fine particles. be. Silica particles can be introduced into the membrane by adding colloidal silica, for example. Metal oxide fine particles have an excellent effect of transmitting the stress applied to the antifogging film to the transparent article that supports the film, and have high hardness. Therefore, the addition of metal oxide fine particles is advantageous from the viewpoint of improving the abrasion resistance and scratch resistance of the antifogging film. Furthermore, when metal oxide fine particles are added to the antifogging film, fine voids are formed in areas where the fine particles are in contact with or are 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 have an advantageous effect on improving antifogging properties. The metal oxide fine particles can be supplied to the antifogging film by adding the metal oxide fine particles formed in advance 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, and if it is too small, they will aggregate and become difficult to disperse uniformly. From this point of view, the preferred average particle size of the metal oxide fine particles is 1 to 20 nm, particularly 5 to 20 nm. Note that here, the average particle diameter of metal oxide fine particles is described in the state of primary particles. Further, the average particle size of the metal oxide fine particles is determined by measuring the particle size of 50 arbitrarily selected fine particles by observation using a scanning electron microscope, and employing the average value thereof. If the content of metal oxide fine particles is excessive, the amount of water absorbed by 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 mass, preferably 1 to 30 parts by mass, more preferably 2 to 30 parts by mass, and especially It is preferably added in an amount of 5 to 25 parts by weight, and in some cases 10 to 20 parts by weight.

(Hydrolyzable metal compound without water repellent group)
Further, the antifogging film 9 may contain a metal oxide component derived from a hydrolyzable metal compound that does not have a water-repellent group (a hydrolyzable compound that does not contain a water-repellent group). A preferred hydrolyzable metal compound without a water-repellent group is a hydrolyzable silicon compound without a water-repellent group. The hydrolyzable silicon compound without a water-repellent group is, for example, at least one silicon compound selected from silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane, and aminosilane (but does not have a water-repellent group), Silicon alkoxide without a water-repellent group is preferred. Incidentally, as the alkenyloxysilane, isopropenoxysilane can be exemplified.

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

The hydrolyzable metal compound containing no water-repellent group is hydrolyzed or partially hydrolyzed, and furthermore, at least a portion thereof is polycondensed to provide a metal oxide component in which a metal atom and an oxygen atom are bonded. This component can firmly bond the metal oxide fine particles and the water-absorbing resin, and can contribute to improving the abrasion resistance, hardness, water resistance, etc. of the antifogging film. When the antifogging film contains a water-absorbing resin, the metal oxide component derived from a hydrolyzable metal compound having no water-repellent group is 0 to 40 parts by mass, preferably 0. The amount may range from 1 to 30 parts by weight, more preferably from 1 to 20 parts by weight, particularly preferably from 3 to 10 parts by weight, and in some cases from 4 to 12 parts by weight.

A preferred example of the hydrolyzable silicone compound having no water-repellent group is tetraalkoxysilane, more specifically tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms. Tetraalkoxysilanes include, for example, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane and tetra-tert- 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 decrease. One reason for this is that the flexibility of the antifogging film decreases, limiting swelling and contraction of the film due to absorption and release of moisture. When the antifogging film contains a water absorbent resin, the metal oxide component derived from the tetraalkoxysilane is 0 to 30 parts by mass, preferably 1 to 20 parts by mass, more preferably 3 parts by mass, based on 100 parts by mass of the water absorbent resin. It is preferable to add it in a range of 10 parts by mass.

Another preferred example of a hydrolyzable silicone compound having no water-repellent group is a silane coupling agent. Silane coupling agents are silicon compounds having different reactive functional groups. It is preferable that a part of the reactive functional group is a hydrolyzable functional group. The silane coupling agent is, for example, a silicon compound having an epoxy group and/or an amino group and a hydrolyzable functional group. Examples of preferred silane coupling agents include glycidyloxyalkyltrialkoxysilane and aminoalkyltrialkoxysilane. 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), so although they contain alkylene groups, they are not water repellent as a whole.

The silane coupling agent firmly binds the water-absorbing resin, which is an organic component, and the metal oxide fine particles, which is an inorganic component, and can contribute to improving the abrasion resistance, hardness, water resistance, etc. of the antifogging film. However, when the content of the metal oxide (silica) component derived from the silane coupling agent becomes excessive, the antifogging property of the antifogging film decreases, and in some cases, the antifogging film becomes cloudy. When the antifogging film contains a water absorbent resin, the metal oxide component derived from the silane coupling agent is 0 to 10 parts by mass, preferably 0.05 to 5 parts by mass, or more, based on 100 parts by mass of the water absorbent resin. It is preferably added in an amount of 0.1 to 2 parts by mass.

[Crosslinked structure]
Further, the antifogging film 9 may include a crosslinked structure derived from a crosslinking agent, preferably at least one crosslinking agent selected from an organic boron compound, an organic titanium compound, and an organic zirconium compound. Introduction of the crosslinked structure improves the abrasion resistance, scratch resistance, and water resistance of the antifogging film. Stated from another perspective, the introduction of the crosslinked structure facilitates improving the durability of the antifogging film without reducing its antifogging performance.

When a crosslinked structure derived from a crosslinking agent is introduced into an antifogging film whose metal oxide component is a silica component, the antifogging film contains silicon and metal atoms other than silicon, preferably boron, titanium, or zirconium, as metal atoms. May contain.

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

Preferred crosslinking agents when the water-absorbing resin is polyvinyl acetal are organic titanium compounds, especially titanium lactate.

[Other optional ingredients]
The antifogging film 9 may also 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, ultraviolet absorbers, colorants, antifoaming agents, preservatives, and the like.

[Film thickness]
The thickness of the antifogging film 9 may be adjusted as appropriate depending on the required antifogging properties and other factors. The preferred thickness of the antifogging film 9 is 1 to 20 μm, preferably 2 to 15 μm, particularly 3 to 10 μm.

[Film formation]
The anti-fog film 9 is produced by applying a coating liquid for forming the anti-fog film 9 onto a transparent article such as a transparent substrate, drying the applied coating liquid, and further subjecting it to high-temperature and high-humidity treatment, etc., if necessary. By carrying out this process, a film can be formed. Conventionally known materials and methods may be used for the solvent used to prepare the coating liquid and the method for applying 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 most 30%. Keeping the relative humidity low prevents the membrane from absorbing too much moisture from the atmosphere. If a large amount of water is absorbed from the atmosphere, the remaining water that enters the membrane matrix may reduce the strength of the membrane.

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

In order to avoid decomposition of organic substances such as water-absorbing resins, the temperature applied in the heating and drying step should not be excessively high. In this case, the appropriate heating temperature is 300°C or less, for example 100 to 200°C, and the heating time is 1 minute to 1 hour.

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

Further, the antifogging film 9 formed from the coating liquid may be washed and/or wiped with a damp cloth, if necessary. Specifically, this 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 in water. Pure water is suitable for these purposes. It is best to avoid using solutions containing detergents for cleaning. Through this step, dust, dirt, etc. adhering to the surface of the antifogging film 9 can be removed, and a clean coating surface can be obtained.

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 based on 100 parts by mass of the water-absorbing resin. At this time, the water-repellent group is a chain alkyl group having 1 to 8 carbon atoms, and the water-repellent group is directly bonded to a metal atom constituting the metal oxide component, and the metal atom may be silicon. . Further, at least a part of the metal oxide component is derived from a hydrolyzable metal compound or a hydrolyzate of a hydrolyzable metal compound added to the coating solution for forming the antifogging film. The hydrolyzable metal compound may be at least one selected from a hydrolyzable metal compound having a water-repellent group and a hydrolyzable metal compound not having a water-repellent group. Furthermore, the hydrolyzable metal compound having no water-repellent group may contain at least one selected from tetraalkoxysilane and a silane coupling agent. By forming the anti-fog film 9 in this manner, it is possible to suppress fogging of the information acquisition area 23, and the information acquisition device can appropriately acquire information outside the vehicle. Note that when the anti-fog film 9 is disposed on the fourth surface 222, the information acquisition area heating unit 5 should be placed in place so that the information acquisition area heating unit 5 does not come into direct contact with the anti-fog film 9, for example, as in the above embodiment. 5 is desirably placed outside the fourth surface 222. Thereby, deterioration of the antifogging film 9 can be prevented.

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

FIG. 20 schematically illustrates a windshield 1D in which a shielding layer 3D is provided to surround an information acquisition region 23D. As illustrated in FIG. 20, the shielding layer 3D according to this modification has a rectangular protrusion region 32 that protrudes inward in the surface 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 embodiment described above, except that it has a protruding region 32. The information acquisition area 23D is provided as a transparent window in this protrusion area 32.

That is, the information acquisition area 23D is an area where the ceramic constituting the shielding layer 3D is not partially coated, and thereby the information acquisition area 23D can be provided within the protruding area 32. The photographing device 8 can photograph the situation outside the vehicle via this information acquisition area 23D.

In addition, in this modification, the shielding layer 3D is provided all around the information acquisition area 23D. However, the shape of the shielding layer 3D is not limited to this example, and at least one of the left and right portions and the lower portion of the information acquisition region 23D may be omitted. That is, the portion of the shielding layer 3D where the bus bar portion 51 is not arranged may be omitted.

<3.5>
Further, for example, in the embodiment described above, the photographing device 8 is used as the information acquisition device. However, the information acquisition device is not limited to this example as long as it is a device that can acquire information from outside the vehicle by emitting and/or receiving light, and may be used as appropriate depending on the embodiment. May be selected. For example, information acquisition devices include visible light and/or infrared cameras for measuring the distance between vehicles, light receiving devices such as optical beacons that receive signals from outside the vehicle, and visible light and/or infrared cameras that read images of road white lines, etc. Various devices may be used, such as a camera using infrared light.

Further, a plurality of information acquisition devices may be used, and a stereo camera including 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 photographing devices. Furthermore, the information acquisition area heating unit 5 may be provided in all of the plurality of information acquisition areas 23, or the information acquisition area heating unit 5 may be provided in at least one of the plurality of information acquisition areas 23. 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 information acquisition regions 23 and the number and arrangement of information acquisition region heating units 5 may be selected as appropriate depending on the embodiment.

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

<3.7>
Further, for example, in the embodiment described above, 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 does not need to be limited to this example, and may be appropriately selected depending on the embodiment. For example, the shielding layer 3 may be laminated on the second surface 212 and/or the third surface 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 for forming the laminated glass 2 does not need to be limited to such an example, and may be appropriately selected depending on 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 embodiment, the intermediate layer 4 has a total of three layers: 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. It consists of However, the configuration of the intermediate layer 4 does not need to be limited to such an example, and may be appropriately selected depending on 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 embodiment described above, 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. This three-layered shielding layer 3 can shield electromagnetic waves with the silver layer. Note that materials having the compositions shown in Table 2 below can be used for this silver layer.

*1, Main ingredients: Bismuth borosilicate, zinc borosilicate

<3.11>
Further, for example, in the above embodiment, each of the heating wires 52A to 52C is formed in a substantially U-shape. However, the shape of each of the heating wires 52A to 52C is not limited to this example, and may be formed as appropriate so that they can pass through the information acquisition area 23 and be connected to both busbar sections 51. In other words, the shape of each of the heating wires 52A to 52C is particularly suitable if the shape extends inward in the plane direction from one busbar section 51, passes through the information acquisition area 23, is turned back, and extends toward the other busbar section 51. It does not have to be limited. For example, each heating wire may be formed as illustrated in FIG.

FIG. 21 is an enlarged view schematically illustrating the information acquisition area heating section 5E according to this modification. This information acquisition area heating section 5E includes two heating wires (54A, 54B) arranged in parallel. The first heating wire 54A is located on the outside, and the second heating wire 54B is located on the inside. Both heating wires (54A, 54B) both extend from one bus bar section 51 toward the information acquisition area 23, pass through the information acquisition area 23, and are folded back and extend toward the other bus bar section 51 near the center. It has folded portions (541A, 541B) that are folded back toward each bus bar portion 51. Thus, each heating wire may include a folded portion. Thereby, even if the number of heating wires is small, the information acquisition area 23 can be heated evenly.

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 placed on the outside is longer than the second heating wire 54B placed on the inside. Therefore, from the relational expressions 1 to 3 above, there is a possibility that the calorific value of the first heating wire 54A disposed on the outside 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 both heating wires (54A, 54B) generate approximately 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, 223-226...Notch,
23...information acquisition area,
3... Shielding layer, 31... Band-shaped region,
4... Intermediate layer, 41... Base material, 42, 43... Adhesive layer,
5... Information acquisition area heating section, 51... Bus bar section, 52A to 52C... Heating wire,
6... Other area heating section, 61... Bus bar section, 62... Heating wire,
71...Connecting material, 72...Fixing material, 73...Connecting material, 74...Fixing material,
8... Photographing device, 81... Image processing device,
9...Anti-fog film,
11... Release film, 12... Adhesive layer

Claims (10)

An automobile windshield in which an information acquisition device that acquires information from outside the vehicle by emitting 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 provided on the glass plate and shielding the view from outside the vehicle;
an information acquisition area heating unit that has a pair of busbar units and a plurality of heating wires and heats the information acquisition area;
Equipped with
The shielding layer includes a band-shaped region extending along an edge of the glass plate,
The information acquisition region is arranged adjacent to the inner side of the strip-shaped region in the plane direction,
The shielding layer is not provided around the information acquisition area except for a portion of the outer edge of the information acquisition area that is adjacent to the band-shaped area in the surface direction, and
Both busbar parts of the information acquisition area heating part are arranged side by side so as to be included in the band-shaped area in the viewing direction,
The line width of each heating line of the information acquisition area heating section is 5 μm or more and 15 μm or less,
Each heating wire of the information acquisition area heating section is connected to both the busbar sections in parallel, extends inward in the plane direction from one busbar section, passes over the information acquisition area, and is folded back to connect to the other busbar section. extending in the direction
windshield. Among the plurality of heating wires, the heating wire that extends further inward in the plane direction has a larger cross-sectional area;
The windshield according to claim 1 . At least one of the adjacent heating wires among the plurality of heating wires each has a portion extending in parallel to each other,
Each of the parallel extending portions of the heating wires adjacent to each other is formed in a wave shape.
The 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;
The windshield according to claim 3 . an anti-fog 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 an other area heating unit having one or more heating wires and heating an area other than the information acquisition area;
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 section is different from the amount of heat generated per unit area of the other area heating section,
The windshield according to claim 7 . The cross-sectional area of each heating wire of the information acquisition area heating section is larger than that of the heating wire of the other area heating section.
The windshield according to claim 8 . The cross-sectional area of each heating wire of the information acquisition area heating section is smaller than the heating wire of the other area heating section.
The windshield according to claim 8 .