JP2020115467A - Windshield - Google Patents

Abstract

To provide a windshield including a shield layer having a high degree of design freedom.SOLUTION: A windshield 1 comprises laminated glass 2 obtained by joining an exterior side glass plate disposed at a vehicle exterior side with an interior side glass plate disposed on the vehicle interior side using an intermediate layer. Along a periphery of the laminated glass 2 is provided a shield layer 3 for performing shielding from viewing from the outside of a vehicle. An information acquisition region heating part 5 comprises a pair of bus bar parts 51 and three heating lines 52A to 52C connected in parallel to both the bus bar parts 51. The heating lines 52A to 52C extend inward in a surface direction from one of the bus bar parts 51, pass over an information acquisition region 23, and are folded back to connect with the other of the bus bar parts 51.SELECTED DRAWING: Figure 3

Description

The present invention relates to a windshield for automobiles.

For example, in a place where the temperature is low, the windshield of the automobile may become cloudy or may be frozen depending on the temperature difference between the inside and outside of the vehicle, which may hinder driving. To address this, various methods have been proposed to remove windshield fogging or ice. For example, Patent Document 1 proposes disposing a bus bar and a heating wire inside a windshield to remove fogging by heat generation thereof.

Further, in recent years, an in-vehicle system has been proposed in which a camera for photographing the situation outside the vehicle is installed inside the vehicle. This in-vehicle system recognizes oncoming vehicles, vehicles in front, pedestrians, traffic signs, lane boundaries, etc. by analyzing the captured image of the subject acquired by the camera, and informs the driver of various dangers. Can provide driving assistance.

However, in general, along the peripheral portion of the windshield, a shielding layer for shielding the field of view from the outside of the vehicle is provided, while the camera of the vehicle-mounted system is It is installed at a position where the shielding layer can be included in the shooting range of the camera. Therefore, there is a possibility that the shielding layer may interfere with the shooting by the camera.

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

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

Since the transmissive window is also part of the windshield, the transmissive window may fog and freeze along with other areas. Therefore, it is conceivable to dispose the heating wire as described above also in the transmissive window to remove fogging and/or ice. However, the present inventors have found that if the bus bar and the heating wire are arranged as in the conventional case, the following problems occur.

The problems found by the present inventors will be described with reference to FIGS. 1 and 2. FIG. 1 schematically illustrates a windshield 100 according to a conventional example. Further, FIG. 2 schematically illustrates the configurations of the bus bar portion 104 and the heating wire 105 according to the conventional example. As illustrated in FIG. 1, in the conventional windshield 100, the shielding layer 101 is provided along the peripheral portion.

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

At this time, assuming that a heating unit that heats the transmission window 103 is configured as in the conventional example illustrated in Patent Document 1, the bus bar unit 104 and the heating unit 105 that configure the heating unit are illustrated in FIG. Is located in. That is, the pair of bus bar portions 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 the bus bar portions 104 in parallel.

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

The present invention, in one aspect, has been made in view of such circumstances, and an object thereof is to provide a windshield having a high degree of freedom in designing a shielding layer.

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

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

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

Further, as another mode of the windshield according to the above configuration, in the plurality of heating wires, the heating wire extending inward in the surface direction may have a larger cross-sectional area. With the same cross-sectional area, the longer the length of the heating wire, the smaller the amount of heat generation of the heating wire, according to the relational expression of Equation 1 described later. Therefore, if all the heating wires have the same cross-sectional area, the amount of heat generated by the heating wires extending further outward in the planar direction becomes smaller, and it may not be possible to uniformly heat the entire information acquisition region. As a result, clouding and/or ice may partially remain in the information acquisition area, or a part in which the removal of clouding and/or ice is delayed may occur. On the other hand, according to the configuration, by increasing the cross-sectional area of the heating wire extending inward in the plane direction, the difference in the amount of heat generated between the heating wire extending further inward in the plane direction and the heating wire not extending in the plane direction. Can be reduced. Therefore, according to the said structure, it becomes possible to heat an information acquisition area|region uniformly, and by this, it becomes possible to remove clouding and/or ice of an information acquisition area appropriately. When the thickness of each heating wire is substantially constant, the cross-sectional area of each heating wire is proportional to the line width of each heating wire (may be referred to as "wire diameter"). Therefore, in this case, the size of the cross-sectional area of each heating wire can be easily changed by adjusting the line width of each heating wire.

Further, as another form of the windshield according to the above configuration, at least one of adjacent heating wires of the plurality of heating wires may have portions extending in parallel with each other, and The portions extending in parallel may each be formed in a wavy shape. When adjacent heating lines have portions extending in parallel with each other and the parallel portions of the heating lines adjacent to each other are formed in a straight line, the light is diffracted in one direction due to the diffraction of light generated at the edge of this portion. The strengthening of each other occurs. As a result, a linear pattern having high light intensity is generated, which may adversely affect the acquisition of information by the information acquisition device. On the other hand, by forming the portions of the heating wires adjacent to each other that extend in parallel to each other in a wavy shape, it is possible to disperse the directions in which light intensification occurs in multiple directions, and weaken the light intensity of the pattern that occurs in each direction. be able to. Therefore, according to the configuration, it is possible to prevent the diffraction of the light, which has a bad influence on the information acquisition by the information acquisition device, in the plurality of heating wires.

As another form of the windshield according to the above configuration, the wavy patterns of the portions of the adjacent heating wires that extend in parallel may be offset from each other. With this configuration, the direction in which the light beams are strengthened can be dispersed in the other direction, and the light intensity of the pattern generated in each direction can be weakened. Therefore, according to this configuration, it is possible to make it more difficult for the plurality of heating lines to undergo light diffraction that adversely affects the acquisition of information by the information acquisition device.

Further, as another form of the windshield according to the above configuration, an antifogging film may be attached to the information acquisition area. According to this configuration, the information acquisition area can be made more difficult to fog.

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

Further, as another mode of the windshield according to the above configuration, the windshield may include one or a plurality of heating wires and may further include another area heating unit that heats an area other than the information acquisition area. According to this configuration, it is possible to remove the cloudiness and/or ice in the area other than the information acquisition area.

Further, as another form of the windshield according to the above configuration, the heat generation amount per unit area of the information acquisition region heating unit may be different from the heat generation amount per unit area of the other region heating unit. The reason for warming may differ between the information acquisition area and other areas. For example, it is assumed that the information acquisition area is warmed to remove fogging, and the other areas are warmed to remove (melt) ice. In such a case, it is not necessary to heat the information acquisition area and the other area with the same amount of heat generation. According to the configuration, by setting the heat generation amount per unit area of the information acquisition region heating unit and the heat generation amount per unit area of the other region heating unit to be different from each other, it is possible to meet such a request. it 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 unit may be larger than that of the heating wire of the other area heating unit. Thereby, the heat generation amount per unit area of the information acquisition region heating unit can be made larger than that of the other region heating unit. On the other hand, the cross-sectional area of each heating wire of the information acquisition area heating unit may be smaller than that of the heating wire of the other area heating unit. Thereby, the heat generation amount per unit area of the information acquisition region heating unit can be made smaller than that of the other region heating unit.

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

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

Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. However, the present embodiment described below is merely an example 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 present invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be appropriately adopted. Note that, in the following description, for convenience of description, the description will be given based on the orientation in the drawing.

§1 Configuration Example First, the windshield 1 according to the present embodiment will be described with reference to 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. Further, FIGS. 5 and 6 schematically exemplify the cross sections taken along the lines AA and BB of FIG. 3, respectively.

As shown in each drawing, the windshield 1 according to the present embodiment includes a laminated glass 2 in which an outer glass plate 21 arranged on the outer side of the vehicle and an inner glass plate 22 arranged on the inner side of the vehicle are joined by an intermediate layer 4. I have it. The laminated glass 2 corresponds to the “glass plate” of the present invention. A shielding layer 3 that shields the visual field from the outside of the vehicle is provided along the peripheral edge of the laminated glass 2.

In the present embodiment, as illustrated in FIG. 3 and FIG. 4, the shielding layer 3 has a strip shape extending along the upper end side of the laminated glass 2 substantially at the center of the portion along the upper end side of the laminated glass 2. Area 31 is set. In addition, a bracket (not shown) is provided in the interior of the automobile to which the laminated glass 2 is attached so that the area on the inner side (that is, the lower side) of the strip-shaped area 31 in which the shielding layer 3 is not provided enters the angle of view. The image capturing device 8 is attached via the above. As a result, the information acquisition area 23, which faces the imaging device 8 and through which light passes, is set so as to be adjacent to the inside of the strip-shaped area 31 in the surface direction. That is, the busbar portion 51 is arranged in the strip-shaped area 31, and the information acquisition area 23 is arranged inside the busbar portion 51 in the plane direction. The photographing device 8 corresponds to the “information acquisition device” of the present invention.

Further, in the present embodiment, the intermediate layer 4 is provided with the information acquisition region heating unit 5 that heats the information acquisition region 23 and the other region heating unit 6 that heats a region other than the information acquisition region 23. The inner glass plate 22 is provided with notches 223 to 226 so that terminals can be connected to the respective heating parts (5, 6). This makes it possible to remove the fog and/or ice in the information acquisition area 23 and other areas. Hereinafter, each component will be described.

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

Both glass plates (21, 22) have substantially the same shape, and are formed in a trapezoidal shape in a 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 well-known glass plate can be used for each glass plate (21, 22). For example, each glass plate (21, 22) may be heat ray 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 vehicle is used. For example, each glass plate (21, 22) may be configured to have a transmittance of visible light (380 nm to 780 nm) of 70% or more, as defined by JIS R 3211. The transmittance can be measured by a spectroscopic measurement method specified in JIS Z 8722, as specified in JIS R 3212 (3.11 visible light transmittance test). In addition, for example, the outer glass plate 21 can secure a desired solar absorptance, and the inner glass plate 22 can adjust the visible light transmittance so as to satisfy the safety standard. Below, as an example of the composition of glass which can comprise each glass plate (21, 22), an example of a composition of clear glass and an example of a heat ray absorption glass composition are shown.

(Clear glass)
SiO _2: 70~73 mass%
Al ₂ O _3: 0.6~2.4 wt%
CaO: 7 to 12 mass%
MgO: 1.0-4.5 mass%
R ₂ O: 13 to 15 mass% (R is an alkali metal)
Fe total iron oxide in terms of _{2 O 3 (T-Fe 2} O 3): 0.08~0.14 wt%

(Heat absorption glass)
The composition of the heat-absorbing glass, for example, based on the composition of the clear glass, the proportion of the total iron oxide in terms of _{Fe 2 O 3 (T-Fe} 2 O 3) and 0.4 to 1.3 wt%, CeO ₂ ratio as 0-2 mass%, the proportion of TiO ₂ and 0 to 0.5 wt%, framework component of the glass (mainly, SiO ₂ and Al ₂ O ₃₎ to T-Fe ₂ O _3, CeO _The composition can be obtained by reducing the increments of ₂ and TiO ₂ .

The thickness of the laminated glass 2 according to the present embodiment is not particularly limited, but from the viewpoint of weight reduction, the total thickness of both glass plates (21, 22) is preferably 2.5 mm to 10.6 mm, The thickness is more preferably 2.6 mm to 3.8 mm, and particularly preferably 2.7 mm to 3.2 mm. Thus, in order to reduce the weight, the total thickness of both glass plates (21, 22) may be reduced. The thickness of each glass plate (21, 22) is not particularly limited, but 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 the impact of flying objects such as pebbles. On the other hand, as the thickness of the outer glass plate 21 is increased, the weight is increased, 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 is adopted can be appropriately determined according to the embodiment.

On the other hand, the thickness of the inner glass plate 22 can be made equal to the thickness of the outer glass plate 21, but for example, in order to reduce the weight of the laminated glass 2, the thickness can be made smaller than that of the outer glass plate 21. .. Specifically, considering the strength of the glass, the thickness of the inner glass plate 22 is preferably 0.6 mm to 2.1 mm, more preferably 0.8 mm to 1.6 mm, and 1.0 mm. It is particularly preferable that it is ˜1.4 mm. Further, the thickness of the inner glass plate 22 is preferably 0.8 mm to 1.3 mm. Which thickness is adopted also for the inner glass plate 22 can be appropriately determined according to the embodiment.

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

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

In the present embodiment, the strip-shaped region 31 is provided at the substantially center of the portion along the upper edge of the laminated glass 2, and the information acquisition region 23 is provided below and adjacent to the strip-shaped region 31. As shown in FIG. 4, the image capturing device 8 disposed inside the laminated glass 2 inside the vehicle captures an image of the situation outside the vehicle through the information acquisition area 23. Therefore, the information acquisition region 23 may be configured to have a visible light transmittance of 70% or more as defined by JIS R 3211 as described above.

The dimensions of each part of the shielding layer 3 may be appropriately set according to the embodiment. For example, the width of the portion along the upper edge and the lower edge of the laminated glass 2 may be set in the range of 20 mm to 100 mm. Moreover, the width of the part along each of the left edge and the right edge of the laminated glass 2 may be set in the range of 15 mm to 70 mm.

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

*1, Asahi Chemical Industry Co., Ltd.: Black 6350 (Pigment Green 17)
*2: Main component: Bismuth borosilicate, Zinc borosilicate

Moreover, the strip|belt-shaped area|region 31 can be set in the range of 10 mm-50 mm in width 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 a straight line. However, the shape of the lower end side of the band-shaped region 31 may not be limited to such an example. For example, the lower end of the band-shaped region 31 may be curved or uneven in the range of 10 mm to 50 mm in width.

Further, in FIG. 3, the band-shaped area 31 and the information acquisition area 23 are slightly apart from each other. The phrase "the information acquisition region is arranged adjacent to the inner side of the strip-shaped region in the surface direction" does not have to be the connection between the information acquisition region and the strip-shaped region, and may include such a state of being slightly separated.

[Middle layer]
Next, the intermediate layer 4 will be described. In the present 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 unit 5 and the other area heating unit 6, and a pair of adhesive layers (42, 43) sandwiching the heat generating layer. Each layer will be described below.

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

(Information acquisition area heating unit)
The information acquisition area heating unit 5 is configured to heat the information acquisition area 23 set on the laminated glass 2 to remove clouding and/or ice in the information acquisition area 23. Specifically, as illustrated in FIGS. 3 to 5, the information acquisition region heating unit 5 is connected to the pair of bus bar units 51 arranged on the base material 41 and both bus bar units 51 in parallel. It is provided with three heating wires 52A to 52C. In addition, below, for convenience of description, these are also referred to as a first heating wire 52A, a second heating wire 52B, and a third heating wire 52C.

As shown in each drawing, both bus bar portions 51 are arranged so as to be included in the strip-shaped region 31 of the shielding layer 3 in the viewing direction. The visual field direction is the visual field direction of the driver and the companion sitting in the passenger seat when the windshield 1 is attached to the automobile, and is, for example, a direction perpendicular to the paper surface of FIG. 3 (each glass plate (21, 22)). ) Is perpendicular to the plane). In addition, as shown in FIG. 3, both bus bar portions 51 are arranged side by side in the extending direction of the strip region 31, that is, in the left-right direction. Further, both bus bar portions 51 are arranged inside the respective notches (223, 224) in the surface direction so as not to be exposed from the respective notches (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 (i.e., downward) in the plane direction from one bus bar portion 51, passes over the information acquisition region 23, is folded, and is connected to the other bus bar portion 51.

In the present 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 lateral 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 the both lateral 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 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 heating wires 52A to 52C may have a line width of, 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~52C, for example, can be 1μm ² ~250000μm ^2, it is preferably from 25μm ² ~10000μm ^2, a 25μm ² ~225μm ² Is more preferable. The cross-sectional area of each of the heating wires 52A to 52C can be measured, for example, by observing a cross section magnified 150 times using a microscope. In addition, the cross-sectional area may vary within each of the heating wires 52A to 52C. In this case, the measurement area of the cross-sectional area may be set at the center of each heating wire 52A to 52C. Further, the heating wires 52A to 52C may have the same cross-sectional area. However, regarding the heat generation amount of each of the heating wires 52A to 52C, the following relational expressions of Equations 1 to 3 are known.

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

From the above Equations 1 to 3, when the cross-sectional area is the same, the longer the heating wire, the smaller the heating value (W) of the heating wire. Therefore, if the heating wires 52A to 52C have the same cross-sectional area, the heating value of the heating wire becomes smaller as the heating wire extends from the both bus bar portions 51 to the inner side in the plane direction.

That is, the heating value of the second heating wire 52B becomes smaller than that of the third heating wire 52C, and the heating value of the first heating wire 52A becomes smaller than that of the second heating wire 52B. As a result, there is a possibility that the entire information acquisition area 23 cannot be uniformly heated. In particular, in the information acquisition area 23, the amount of heat generation becomes small in the portion away from both bus bar portions 51, and there is a possibility that fogging and/or ice removal may be delayed in this portion.

Therefore, in the present embodiment, the heating wires 52A to 52C may have different cross-sectional areas. Specifically, the heating wire extending from both bus bar portions 51 to the inner side in the plane direction may have a larger cross-sectional area. That is, the cross-sectional area of the second heating wire 52B may be larger than that of the third heating wire 52C, and the cross-sectional area of the first heating wire 52A may be larger than that of the second heating wire 52B. As a result, the difference in the amount of heat generated by each of the heating wires 52A to 52C can be suppressed, and the information acquisition area 23 can be uniformly heated.

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

The size of each bus bar portion 51, the distance between both bus bar portions 51, and the distance between the heating wires 52A to 52C may be appropriately set according to the embodiment. However, when both bus bar portions 51 and the heating wires 52A to 52C have substantially the same thickness, if the width of each bus bar portion 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 becomes smaller than 5 mm when the heating wires 52A to 52C have a line width of 500 μm), each bus bar portion 51 itself may cause abnormal heat generation. This may reduce the heat generation efficiency of the information acquisition area heating unit 5. Further, if the size of each bus bar portion 51 is too small, it may be difficult to connect the connection terminal (anode terminal or cathode terminal: not shown) provided in each bus bar portion 51. On the other hand, if the size of each bus bar portion 51 is too large, each bus bar portion 51 may protrude from the shielding layer 3 and obstruct the visual field. From these viewpoints, the size of each bus bar portion 51 may be set to, for example, 5 mm (horizontal)×5 mm (vertical) to 60 mm (horizontal)×60 mm (vertical). Further, the distance between both bus bar portions 51, that is, the distance between the horizontal centers of the bus bar portions 51 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 is preferably 10 mm to 50 mm. Furthermore, for example, the space 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 is preferably 10 mm to 40 mm.

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

As shown in FIG. 5, each connecting member 71 is formed in a rectangular shape, and is sandwiched between each bus bar portion 51 and the adhesive layer 43. Then, each connecting material 71 is fixed to each bus bar portion 51 by a fixing material 72 such as solder. For the fixing material 72, it is preferable to use, for example, a solder having a low melting point of 150° C. or less so that the fixing material 72 can be fixed at the same time by an autoclave at the time of assembling a windshield 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 from each notch (223, 224) formed in the upper edge of the inner glass plate 22. .. Then, in this exposed portion, by connecting the connection terminals of the cable extending from the power source of the automobile with a fixing material such as solder, electricity is supplied from the power source to the heating wires 52A to 52C through the bus bar portions 51 to heat them. Will be able to.

In this way, the connecting members 71 fix the connection terminals to the portions exposed from the notches (223, 224) of the inner glass plate 22 without protruding from the ends of the both glass plates (21, 22). You can do it. Note that each connecting member 71 may be formed of a thin material, and in that case, the end portion can be fixed to each bus bar portion 51 by the fixing member 72 after being bent.

(Other area heating section)
On the other hand, the other area heating unit 6 heats an area other than the information acquisition area 23 of the laminated glass 2, in particular, a visual field area (area within the visual field) of the driver and a companion sitting in the passenger seat, and the information acquisition area 23. It is a structure for removing cloudiness and/or ice in this area other than. Specifically, as illustrated in FIG. 3 to FIG. 6, the other area heating unit 6 and the pair of bus bar portions 61 arranged on the base material 41 extend in the left-right direction, and are connected to both the bus bar portions 61. It has a plurality of heating wires 62 connected in parallel. In FIG. 3, the number of heating wires 62 is six. However, the number of heating wires 62 may not be limited to such an example, and may be appropriately selected according to the embodiment. The number of the heating wires 62 may be 1 to 5, or 7 or more.

As shown in FIG. 3, each bus bar portion 61 is formed so as to extend along each of the left and right edges. The bus bar portions 61 are arranged inward in the plane direction of the notches (225, 226) so as not to be exposed from the notches (225, 226) formed on the left and right ends of the inner glass plate 22. There is. Further, each bus bar portion 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 size of each bus bar portion 61 may be appropriately set according to the embodiment. However, when the width of each bus bar portion 61 is smaller than 10 times the line width of the heating wire 62 when the bus bar portions 61 and the heating wire 62 have the same thickness (for example, the line width of the heating wire 62 is If the width of each bus bar portion 61 is smaller than 5 mm in the case of 500 μm), each bus bar portion 61 itself may generate abnormal heat. As a result, the heat generation efficiency of the other area heating unit 6 may be reduced. On the other hand, if the width of each bus bar portion 61 is larger than 50 mm, each bus bar portion 61 may protrude from the shielding layer 3 and obstruct the visual field. Therefore, the width of each bus bar portion 61 is preferably, for example, 5 mm to 50 mm. In order to suppress heat generation of each bus bar portion 61 itself, it is preferable to make the width of each bus bar portion 61 smaller than 10 times the line width of the heating wire 62. The bus bar portions 61 do not have to be formed along the base material 41 exactly. That is, each bus bar portion 61 does not have 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 bus bar portions 61. The heating wires 62 are arranged substantially parallel to each other in the vertical direction. The line width and spacing of each heating wire 62 may be set appropriately according to the embodiment. For example, a driver and a companion who are seated in the passenger seat in a vehicle equipped with the windshield 1 confirm the condition outside the vehicle through the area where the heating wires 62 are provided. From this viewpoint, the line width of each heating wire 62 is preferably 3 μm to 20 μm, more preferably 5 μm to 13 μm, and particularly preferably 8 μm to 10 μm. The interval between the adjacent heating wires 62 may be 1 mm to 100 mm, preferably 1 mm to 50 mm, and more preferably 1 mm to 10 mm.

The heat generation amount per unit area of the information acquisition region heating unit 5 may be different from the heat generation amount per unit area of the other region heating unit 6. The other area heating unit 6 warms the visual field area of the driver and the accompanying person sitting in the passenger seat, whereas the information acquisition area heating unit 5 warms an area (information acquisition area) within the angle of view of the imaging device 8. .. Therefore, the heating range of each heating unit (5, 6) is large, and the purpose of heating may be different. Therefore, it is not necessary to heat the information acquisition area 23 and other areas with the same amount of heat generation.

For example, it is assumed that the information acquisition area 23 is warmed to remove fogging and the other areas are warmed to remove ice. In such a case, it is preferable to set the heat generation amount per unit area in the other area heating unit 6 to be larger than that in the information acquisition area heating unit 5. As described above, the heat generation amount per unit area of the information acquisition region heating unit 5 may be different from the heat generation amount per unit area of the other region heating unit 6.

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

Further, in the present embodiment, as shown in FIGS. 3 and 6, in the same manner as the information acquisition region heating unit 5, since the bus bar unit 61 and the heating wire 62 are energized, the connecting member 73 and the fixing member 74 are provided. Is used. The connecting member 73 corresponds to the connecting member 71, and the fixing member 74 for fixing the connecting member 71 to each bus bar portion 61 corresponds to the fixing member 72.

That is, each connecting member 73 is connected to each bus bar portion 61 by the fixing member 74, and then each notch (225, 225, notch) of the inner glass plate 22 does not protrude from the end of both glass plates (21, 22). The connection terminal can be fixed to the portion exposed from 226). Then, at the exposed portion, the connection terminals of the cable extending from the power source of the automobile are connected by a fixing material such as solder, so that electricity can be applied to each heating wire 62 via each bus bar portion 61 to heat them. become.

In addition, when the defrosting and/or the defrosting by the heating wire is not performed in the area other than the information acquisition area 23, the other area heating unit 6 may be omitted.

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

Moreover, each bus bar part (51, 61) of each heating part (5, 6) and each heating wire (52A-52C, 62) are copper (or copper plated using tin etc.), tungsten. , Silver, gold, aluminum, alloys thereof, and the like. Here, each bus bar part (51, 61) and each heating wire (52A to 52C, 62) may be formed of the same material or may be formed of different materials. However, copper is a material that can be easily processed. Moreover, since copper is chemically stable, it can be processed using a chemical processing method. Furthermore, copper is an inexpensive material compared to silver or the like. Therefore, from the viewpoint of manufacturing cost, it is preferable to use copper as the material of each heating part (5, 6). Also, by manufacturing each bus bar portion (51, 61) from 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 forming each bus-bar part (51, 61) with copper, since the shielding layer 3 is formed in the 4th surface 222 in this embodiment, each bus-bar part (51, 61) has respect to the shielding layer 3. As a result, each bus bar portion (51, 61) becomes visible from outside the vehicle. As a result, the windshield 1 may look unattractive.

Therefore, when each bus bar portion (51, 61) is formed of copper, the outer surface of each bus bar portion (51, 61), in other words, the surface in contact with the base material 41 is blackened by plating. It is preferable to process it. Thereby, even if the shielding layer 3 is formed on the fourth surface 222, it is possible to make each bus bar portion (51, 61) difficult to visually recognize from the outside of the vehicle.

Then, the formation method of each bus-bar part (51, 61) and each heating wire (52A-52C, 62) is demonstrated. Each bus bar part (51, 61) and each heating wire (52A to 52C, 62) can be formed by arranging a thin wire (wire or the like) previously formed on the base material 41.

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

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

Furthermore, when forming a pattern on the base material 41 by etching, as an example, each bus bar part (51, 61) of each heating part (5, 6) and each heating wire (52A- 52C, 62) can be formed. First, a metal foil is dry-laminated on the base material 41 via the primer layer. As the metal foil, for example, copper can be used. Then, the metal foil is subjected to a chemical etching process using a photolithography method, so that each bus bar portion (51, 61) of each heating portion (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 reduced (for example, 15 μm or less), it is preferable to use a thin metal foil. Therefore, a thin metal layer (for example, 5 μm or less) is formed on the base material 41 by vapor deposition, sputtering or the like, and then each bus bar portion (51, 61) and each heating wire (52A to 52C, 62) is formed by the photolithography method. You may pattern by.

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

The material of each adhesive layer (42, 43) may be appropriately selected depending on the embodiment. For example, polyvinyl butyral resin (PVB), ethylene vinyl acetate (EVA), or the like can be used as the material of each adhesive layer (42, 43). In particular, the polyvinyl butyral resin is preferable because it has excellent adhesiveness to each glass plate (21, 22) as well as excellent penetration resistance. A layer of a surfactant may be provided between each adhesive layer (42, 43) and the heat generating layer. The surface of both layers can be modified by such a surfactant, and the adhesive strength can be improved.

<Other>
The intermediate layer 4 according to this embodiment is configured as described above. The total thickness of the mid 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 0.6 mm to 2.0 mm. Is particularly preferable.

Moreover, the thickness of the base material 41 is preferably 0.01 mm to 2.0 mm, and 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 0.1 mm to 2.0 mm, and 0.1 mm to 1.0 mm. Is more preferable. In addition, in order to improve the adhesiveness between the adhesive layer 43 disposed on the inner glass plate 22 side and the base material 41, each bus bar portion (51, 61) and each heating wire (52A to 52C, 62) sandwiched between them. The thickness of 1) 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 the adhesive layers (42, 43) can be measured, for example, as follows. First, the cross section of the laminated glass 2 is enlarged and displayed 175 times with a microscope (for example, VH-5500 manufactured by Keyence Corporation). Then, the thicknesses of the heat generating layer and the adhesive layers (42, 43) are visually identified and measured. At this time, in order to eliminate visual variations, the number of measurements is set to 5 and the average value thereof is taken as the thickness of the heat generating layer and each adhesive layer (42, 43).

The thicknesses of the heat generating layer and the adhesive layers (42, 43) of the intermediate layer 4 may not be constant over the entire surface, and may be wedge-shaped for laminated glass used in a head-up display, for example. In this case, as for the thickness of the heat generating layer of the intermediate layer 4 and each of the adhesive layers (42, 43), a portion having the smallest thickness, that is, the bottom edge portion of the laminated glass is measured. When the intermediate layer 4 has a wedge shape, the outer glass plate 21 and the inner glass plate 22 are arranged to be inclined with respect to each other. Both glass plates (21, 22) of the laminated glass 2 may not be parallel to each other, but may be arranged so as to be inclined with respect to each other. For example, the intermediate layer 4 using the heat generating layer and the adhesive layers (42, 43) whose thickness increases at a rate of change of 3 mm or less per 1 m may be used.

[Photographing device]
Next, the photographing device 8 will be described. The image capturing device 8 is appropriately configured by a lens system, an image sensor, and the like so that the image outside the vehicle can be captured. The image acquired by the photographing device 8 is sent to the image processing device 81. The image processing device 81 analyzes the type of subject and the like based on the image acquired by the imaging device 8. For example, the type of subject can be estimated by a known image analysis method such as pattern recognition.

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

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

First, a method for manufacturing the laminated glass 2 will be described with reference to FIG. 7. FIG. 7 illustrates a production line for the laminated glass 2. As illustrated in FIG. 7, in the production line of the laminated glass 2, for bending the laminated glass 2, a ring-shaped molding die 200, a carrier 201 that conveys the molding die 200, and a heating furnace 202. And a slow cooling furnace 203.

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

Next, the ceramic printed on each area is appropriately dried. Then, after the ceramic is dried, the outer glass plate 21 and the inner glass plate 22 are vertically stacked so that the second surface 212 and the third surface 221 face each other, thereby forming the flat laminated glass 20. The formed flat laminated glass 20 is placed on the molding die 200. The forming die 200 is arranged on a carrying table 201, and the carrying table 201 sequentially passes through a heating furnace 202 and an annealing furnace 203 with the laminated glass 20 placed on the forming die 200.

When heated to a temperature near the softening point in the heating furnace 202, both glass plates (21, 22) are curved downward due to their own weight inside the peripheral edge portion and curved. Then, both glass plates (21, 22) are carried into the slow cooling furnace 203 from the heating furnace 202, and a slow cooling process is performed. After that, both glass plates (21, 22) are carried out from the annealing furnace 203 and allowed to cool.

After the glass plates (21, 22) are formed in this manner, the intermediate layer 4 is sandwiched between the 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 heat generating layer faces the surface on which the information acquisition area heating unit 5 and the other area heating unit 6 are formed toward the adhesive layer 43 side.

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

Then, the connecting members (71, 73) are inserted from the notches 223 to 226 between the heat generating layer and the adhesive layer 43. At this time, a solder having a low melting point is applied as a fixing material (72, 74) to each connecting material (71, 73), and the solder is arranged on each bus bar portion (51, 61). To do so.

In this way, a laminated body in which the two glass plates (21, 22), the intermediate layer 4, and the connecting materials (71, 73) are laminated is produced. This laminate is put in a rubber bag and pre-bonded at about 70 to 110° C. while suctioning under reduced pressure. The pre-bonding method is not limited to this, and the following method can also be adopted. For example, the laminate is heated in an oven at 45 to 65°C. Next, this laminated body is pressed by a roll at 0.45 to 0.55 MPa. Subsequently, the laminate is heated again in an oven at 80 to 105° C. and then pressed again by a roll at 0.45 to 0.55 MPa. In this way, pre-bonding is completed.

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

The windshield 1 manufactured as described above is attached to the vehicle body, and at that time, the connection terminals are fixed to the respective connection members (71, 73). After that, when each connection terminal is energized, electricity flows to each heating wire (52A to 52C, 62) through each connection member (71, 73) and each bus bar portion (51, 61) to generate heat. As a result, clouding 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 adjacent to the lower side (inside the surface direction) of the strip-shaped region 31 of the shielding layer 3 along the upper edge of the laminated glass 2. The imaging device 8 is installed in the vehicle. The bus bar portions 51 of the information acquisition area heating unit 5 for removing the cloudiness and/or ice in the information acquisition area 23 are arranged side by side in the left-right direction in the strip-shaped area 31 adjacent above the information acquisition area 23. To be done. As a result, both bus bar portions 51 are hidden by the strip-shaped area 31, so that it is not necessary to provide the shielding layer 3 in the area around the information acquisition area 23 except above the information acquisition area 23. That is, instead of arranging the busbar portions 51 so as to sandwich the information acquisition area 23, in the present embodiment, by arranging both busbar portions 51 in an area in any one direction from the information acquisition area 23, The shielding layer 3 may or may not be provided in the region of the direction. As a result, in this embodiment, the degree of freedom in designing the shielding layer 3 can be increased.

§3 Modifications The embodiments of the present invention have been described in detail above, but the above description is merely an example 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 present invention. For example, regarding each constituent element of the windshield 1, the constituent element may be omitted, replaced, or added as appropriate according to the embodiment. Further, the shape and size of each constituent element of the windshield 1 may be appropriately determined according to the embodiment. For example, the following changes are possible. In addition, below, the same code|symbol is used about 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 above embodiment, the strip-shaped region 31 is set in a portion along the upper edge of the laminated glass 2, and the pair of bus bar portions 51 are arranged side by side in the left-right direction so as to be included in the portion. There is. However, the setting position of the band-shaped region 31 is not limited to such an example, and may be appropriately selected according to the embodiment.

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

Here, in FIG. 3, the strip-shaped region 31 is formed in a rectangular shape extending in the left-right direction. However, the strip-shaped region 31 is a region for shielding the pair of bus bar portions 51 arranged side by side, and may extend in at least one direction. Therefore, the shape of the band-shaped region 31 does not have to be rectangular, and may be appropriately selected according to the embodiment.

Further, for example, in the above-described embodiment, the information acquisition area heating unit 5 has three heating wires 52A to 52C. However, the number of heating lines included in the information acquisition region heating unit 5 is not limited to three, and may be two or may be four or more. The number of heating lines provided in the information acquisition area heating unit 5 may be appropriately selected according to the embodiment. Each heating wire is connected in parallel to the bus bar portion 51. As described above, since the information acquisition area heating unit 5 includes the plurality of heating wires, even if one of the heating wires is broken, the information acquisition area 23 can be warmed by the other heating wires.

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

That is, light is diffracted at the ends of the heating wires 52A to 52C. As a result, the light is strengthened or weakened depending on the position, which may adversely affect the shooting by the shooting device 8. Therefore, as shown in FIG. 9, wires were arranged in parallel, light was allowed to pass through the area where the wires were arranged, and it was confirmed how the light was diffracted at the end of each wire. The conditions of each wire and light source are as follows.

(Condition of wire)
・Line width: 10 μm
・Pitch (distance between adjacent wires): 2 mm
(Condition of light source)
・Type of light source: Halogen lamp ・Location: 7m away from the wire

FIG. 10 shows the result of the experiment. As shown in FIG. 10, it was found that when linear wires were arranged in parallel, a linear pattern having a high light intensity was generated in one direction. That is, it has been found that the presence of the above-described portions 522A to 522C may easily adversely affect the image capturing by the image capturing device 8.

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

FIG. 12 shows the result of the experiment. As shown in FIG. 12, it has been found that when the wires have a wavy shape, light is diffracted at the ends of the wires, but the directions in which the light beams are strengthened 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, and thereby the possibility that the diffraction of light generated at the end of the wire may adversely affect the image capturing by the image capturing device 8.

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

FIG. 13 is an enlarged view schematically illustrating the information acquisition area heating unit 5A according to this modification. The heating wires 53A to 53C are configured in the same manner as the heating wires 52A to 52C according to the above-described embodiment except that they are formed in a wavy shape. Here, in the modification shown in FIG. 13, the first heating wire 53A and the second heating wire 53B which are adjacent to each other extend in parallel with each other in three portions 531A to 531C. In each of the portions 531A to 531C, the first heating wire 53A and the second heating wire 53B adjacent to each other are formed in a sinusoidal shape having the same pattern. Further, the second heating wire 53B and the third heating wire 53C which are adjacent to each other extend in parallel with each other in the three portions 532A to 532C. In each of the portions 532A to 532C, the second heating wire 53B and the third heating wire 53C adjacent to each other are formed in a sinusoidal shape having the same pattern. As a result, as shown in FIG. 12, it is possible to reduce the possibility that the imaging of the imaging device 8 will be adversely affected by the diffraction of light that occurs at the end of each heating wire.

Further, as illustrated in FIG. 14, the wavy patterns of the parallel extending portions of the adjacent heating wires may be shifted from each other. FIG. 14 illustrates an example in which the heating wires 53A to 53C are deviated from the sinusoidal pattern. By thus shifting the wavy patterns of the portions of the adjacent heating wires extending in parallel to each other, it is possible to further prevent the linear pattern having a high light intensity as shown in FIG. With this, it is possible to further reduce the possibility that the imaging of the imaging device 8 is adversely affected by the diffraction of light that occurs at the end of each heating wire.

In addition, if a line pattern having a high light intensity as described above is generated, an edge of the line pattern is generated in an image captured using the light incident on the imaging device 8, and for example, However, errors tend to occur in image processing such as pattern recognition. On the other hand, by making the heating wires wavy as described above, the light passing between the heating wires can be flattened, so that an image captured using the light incident on the imaging device 8 is used. In this, it is possible to suppress the occurrence of the edges of the pattern of the line. As a result, it is possible to reduce the possibility that an error will occur when a predetermined image processing is applied to the image obtained by the image capturing device 8. Therefore, when a predetermined image processing is applied to the image obtained by the photographing device 8, it is very difficult to suppress the generation of a linear pattern having a high light intensity by making each heating line wavy as described above. Will be important to.

The same applies to each heating wire 62 of the other area heating unit 6. Therefore, at least the portions of the heating wires 62 that extend in parallel to the adjacent heating wires may be formed in a wavy shape, or the patterns of the wavy portions may be offset from each other. As described above, by forming each heating wire (53A to 53C, 62) in a wavy shape, it is possible to prevent the generation of a linear pattern having a strong light intensity due to the diffraction of light as described above, and It is possible to make it easy to uniformly heat the region where the lines (53A to 53C, 62) are arranged. The shape of each heating wire (53A to 53C, 62) is not limited to the above-described linear shape and wavy shape, and may be appropriately selected according to the embodiment.

<3.2>
Further, for example, in the above-described embodiment, 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 unit 5 and the other area heating unit 6 may not be limited to such an example, and may be appropriately selected according to the embodiment. For example, the information acquisition area heating unit 5 and the other area heating unit 6 may be arranged on either surface of the outer glass plate 21 and the inner glass plate 22.

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

Further, also by the transfer shown in FIGS. 15 and 16A to 16C, the information acquisition area heating unit 5 and the other area heating unit 6 can be arranged on any surface of the outer glass plate 21 and the inner glass plate 22. it can. FIG. 15 illustrates a transfer sheet used for transfer of the information acquisition area heating unit 5 and the other area heating unit 6. 16A to 16C exemplify a process of forming the information acquisition area heating unit 5 and the other area heating unit 6 using the transfer sheet.

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

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

As described above, forming the information acquisition area heating unit 5 and the other area heating unit 6 by the transfer sheet has the following advantages. First, it is easier and more flexible to form the patterns of the information acquisition region heating unit 5 and the other region heating unit 6 on the release film 11 than to form them directly on the laminated glass 2. Therefore, it becomes easy to manufacture a highly structured pattern, a laminated body, and the like. Next, if a large amount of such a transfer sheet is produced, the productivity when forming the information acquisition area heating unit 5 and the other area heating unit 6 on the laminated glass 2 is improved. Furthermore, the information acquisition area heating unit 5 and the other area heating unit 6 can be attached to the uneven surface.

<3.3>
Further, for example, as illustrated in FIG. 17, the anti-fog film 9 may be attached to the information acquisition area 23 according to the above-described embodiment. FIG. 17 illustrates the windshield 1C in which the 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 antifogging film 9 is not particularly limited as long as it has the antifogging effect of the laminated glass 2, and known ones can be used. Generally, types of antifogging film include a hydrophilic type that forms water generated from water vapor as a water film on the surface, a water absorption type that absorbs water vapor, and a water repellent type that repels water droplets generated from water vapor. Any type of antifogging film 9 can be used.

As a result, the information acquisition area 23 can be made less cloudy. Further, for example, in order to remove the fogging of the information acquisition area 23 by the information acquisition area heating unit 5, it takes some time until the heating wires 52A to 52C are energized and heated. Therefore, if the information acquisition area 23 is repeatedly fogged, the loss of time for removing the fog will be correspondingly increased. On the other hand, according to the modified example, the information acquisition area 23 can be made relatively hard to be fogged. Therefore, the number of times the information acquisition area heating unit 5 is used to remove the fog in the information acquisition area 23 can be reduced. It can be reduced, and the time loss can be reduced accordingly.

In the modification, the antifogging film 9 is directly attached to the fourth surface 222 of the inner glass plate 22. However, the disposition of the antifogging film 9 is not limited to such an example, and may be appropriately selected according to the embodiment. For example, the antifogging film 9 can be placed on a sheet-shaped substrate, and then the substrate can be attached to the laminated glass 2 with a transparent adhesive. Further, the pressure-sensitive adhesive, the base material, and the antifogging film 9 can be laminated in this order. The base material can be formed of a transparent resin sheet such as polyethylene or polyethylene terephthalate.

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 absorbent resin. The antifogging film 9 may further contain other functional components, if necessary. The water absorbing resin may be of any type as long as it is a resin capable of absorbing and retaining water. The water-repellent group can be supplied to the antifogging film from a metal compound having a water-repellent group (water-repellent group-containing metal compound). The metal oxide component can be supplied to the antifogging film from a water-repellent group-containing metal compound or other metal compound, metal oxide fine particles, or the like. Hereinafter, each component will be described.

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

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

The average degree of polymerization of polyvinyl alcohol is preferably 200 to 4500, more preferably 500 to 4500. A high average degree of polymerization is advantageous for forming an antifogging film having 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 hinder the formation of the film. is there. The saponification degree of polyvinyl alcohol is preferably 75 to 99.8 mol %.

Examples of the aldehyde to be condensed with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. In addition, benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, other alkyl group-substituted benzaldehyde; chlorobenzaldehyde, other halogen atom-substituted benzaldehyde; alkyl such as hydroxy group, alkoxy group, amino group, and cyano group Substituted benzaldehyde in which a hydrogen atom is substituted with a functional group excluding a group; and aromatic aldehydes such as condensed aromatic ring aldehydes such as naphthaldehyde and anthraldehyde can be mentioned. An aromatic aldehyde having strong hydrophobicity is advantageous in forming an antifogging film having a low degree of acetalization and excellent water resistance. Use of an aromatic aldehyde is also advantageous in forming a film having high water absorption while leaving many hydroxyl groups. The polyvinyl acetal preferably contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

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

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

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 a straight chain alkyl group is preferable. An alkyl group having a carbon number of more than 30 may cloud the antifogging film. From the viewpoints of the antifogging property of the film, the balance of strength and appearance, the chain alkyl group preferably has 20 or less carbon atoms, for example, 1 to 8 and, for example, 4 to 16 and preferably 4 to 8. is there. Particularly preferred alkyl groups are linear alkyl groups having 4 to 8 carbon atoms, for example, n-pentyl group, n-hexyl group, n-heptyl group, and n-octyl group. Regarding (2), the fluorine-substituted alkyl group may be a group obtained by substituting a part of hydrogen atoms of a chain or cyclic alkyl group with a fluorine atom, and all the hydrogen atoms of the chain or cyclic alkyl group. It may be a group in which is substituted with a fluorine atom, for example, a linear perfluoroalkyl group. Since the fluorine-substituted alkyl group has high water repellency, it is possible to obtain a sufficient effect by adding a small amount. However, if the content of the fluorine-substituted alkyl group is too large, it may be separated from other components in the coating liquid for forming the film.

(Hydrolysable metal compound having a water repellent group)
In order to add a water-repellent group to the antifogging film, a metal compound having a water-repellent group (metal compound containing a water-repellent group), particularly a metal compound having a water-repellent group and a hydrolyzable functional group or a halogen atom ( The water-repellent group-containing hydrolyzable metal compound) or a hydrolyzate thereof may be added to the coating liquid for forming the film. In other words, the water repellent group may be derived from a water repellent group-containing hydrolyzable metal compound. As the water-repellent group-containing hydrolyzable metal compound, a water-repellent group-containing hydrolyzable silicon compound represented by the following formula (I) is suitable.
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 a part of hydrogen atoms may be replaced by a fluorine atom, and Y is a hydrolyzable functional group. Is a 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, 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. The functional groups exemplified here can also be used as “hydrolyzable functional groups” described below. m is preferably 1-2.

The compound represented by the formula (I) supplies the components represented by the following formula (II) when the hydrolysis and the polycondensation completely proceed.
R _m SiO _(4-m)/2 (II)
Here, R and m are as described above. After hydrolysis and polycondensation, the compound represented by the formula (II) actually forms a network structure in which silicon atoms are bonded to each other via oxygen atoms in the antifogging film.

Thus, the compound represented by the formula (I) is hydrolyzed or partially hydrolyzed, and at least a part thereof is polycondensed so that silicon atoms and oxygen atoms are alternately connected and three-dimensionally. Form a network structure of spreading siloxane bonds (Si-O-Si). The water-repellent group R is connected to the silicon atom contained in this network structure. In other words, the water-repellent group R is fixed to the siloxane bond network structure through the bond R—Si. This structure is advantageous in uniformly dispersing the water-repellent group R in the film. The network structure may contain a silica component supplied from a silicon compound other than the water-repellent group-containing hydrolyzable silicon compound represented by the formula (I) (for example, tetraalkoxysilane or a silane coupling agent). To form an anti-fog film with a water-repellent group-containing hydrolyzable silicon compound containing a water-repellent group-free hydrolyzable functional group or a halogen atom-containing silicon compound (water-repellent group-free hydrolyzable silicon compound) When blended with the coating liquid of (1), a siloxane-bonded network structure containing silicon atoms bonded to the water-repellent group and silicon atoms not bonded to the water-repellent group can be formed. With such a structure, it becomes easy to independently adjust the content of the water-repellent group and the content of the metal oxide component in the antifogging film.

When the antifogging film contains a water-absorbing resin, the water-repellent group improves the antifogging performance by improving the water vapor permeability on the surface of the antifogging film containing the water-absorbing resin. Since the two functions of water absorption and water repellency are contradictory to each other, the water absorbent material and the water repellent material have been conventionally provided in different layers, but the water repellent group contained in the antifogging film is The uneven distribution of water in the vicinity of the surface of the fog layer is eliminated, the time until dew condensation is extended, and the antifog property of the antifog film is improved. The effect will be described below.

The water vapor that has penetrated into the antifogging film containing the water-absorbent resin is hydrogen-bonded with the hydroxyl groups of the water-absorbent resin and is retained in the form of bound water. As the amount increases, water vapor becomes retained in the form of bound water, through semi-bound water, and finally in the form of free water retained in the voids in the anti-fog film. In the anti-fog film, the water-repellent group prevents formation of hydrogen bond and facilitates dissociation of the formed hydrogen bond. If the water-absorbent resin content is the same, there is no difference in the number of hydroxyl groups capable of hydrogen bonding in the film, but the water-repellent group reduces the rate of hydrogen bond formation. Therefore, in the anti-fogging film containing a water-repellent group, the water content is eventually retained in the film in any of the above-mentioned forms, but by the time it is retained, the water content remains as steam until the bottom of the film. Can spread. Further, water once retained is relatively easily dissociated and easily moves to the bottom of the membrane in the state of water vapor. As a result, the distribution of the amount of water retained in the thickness direction of the film is relatively uniform from the vicinity of the surface to the bottom of the film. That is, since the water supplied to the film surface can be absorbed by effectively utilizing the entire thickness direction of the antifogging film, it is difficult for water drops to condense on the surface and the antifogging property is enhanced.

On the other hand, in the conventional anti-fogging film containing no water-repellent group, the water vapor that has penetrated into 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 film is extremely high near the surface and rapidly decreases toward the bottom of the film. That is, although the bottom portion of the film can still absorb water, it is saturated with water and condensed as water droplets in the vicinity of the surface of the film, so that the antifogging property is limited.

When a water-repellent group is introduced into the antifogging film using a water-repellent group-containing hydrolyzable silicon compound (see Formula (I)), a strong siloxane bond (Si-O-Si) network structure is formed. The 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 to such an extent that the contact angle of water on the surface of the antifogging film is 70 degrees or more, preferably 80 degrees or more, and more preferably 90 degrees or more. For the contact angle of water, a value measured by dropping 4 mg of water droplets on the surface of the membrane is adopted. In particular, when a methyl group or an ethyl group having slightly weak water repellency is used as the water repellent group, it is preferable to mix the water repellent group in an amount such that the contact angle of water falls within the above range in the antifogging film. The upper limit of the contact angle of water 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 antifogging film so that the contact angle of the water is within the above range in all the areas of the surface of the antifogging film.

Here, the relationship between the contact angle of water and the antifogging film 9 will be described with reference to FIGS. 18 and 19. 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 condensing the same amount of water vapor on the surface of the antifogging film 9 covers the contact of water on the surface. Larger corners tend to be smaller. Further, the smaller the area covered by the water droplets (90, 91), the smaller the ratio of the area where the light incident on the antifogging film 9 is scattered. Therefore, the antifogging film 9 having a large contact angle of water due to the presence of the water-repellent group is advantageous in maintaining the straightness of transmitted light in the state where water droplets are formed on the surface thereof.

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

[Metal oxide component]
Next, the metal oxide component will be described. 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, and preferably an oxide component of Si (silica component). ). When the water-absorbent resin is contained, the antifogging film is used in an amount of 0.01 part by mass or more, preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, and further preferably 100 parts by mass of the water-absorbing resin. 1 part by mass or more, particularly preferably 5 parts by mass or more, in some cases 7 parts by mass or more, if necessary 10 parts by mass or more, and 60 parts by mass or less, particularly 50 parts by mass or less, preferably 40 parts by mass or less, It is preferable that the metal oxide component is contained in an amount of 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 component required to secure the strength of the film, especially the scratch resistance, but if the content thereof is excessive, the antifogging property of the film decreases.

At least a part of the metal oxide component may be a hydrolyzable metal compound or a metal oxide component derived from the hydrolyzate added to the coating liquid for forming the antifogging film. Here, the hydrolyzable metal compound has a) a metal compound having a water repellent group and a hydrolyzable functional group or a halogen atom (hydrophobic group-containing hydrolyzable metal compound), and b) a water repellent group. It is at least one selected from metal compounds having non-hydrolyzable functional groups or halogen atoms (water-repellent group-free hydrolyzable metal compounds). 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 liquid for forming an antifogging film, and a hydrolyzable metal compound or its added to the coating liquid. It may contain a metal oxide component derived from a hydrolyzate. Here again, the hydrolyzable metal compound is at least one selected from the above a) and b). The above-mentioned 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. Hereinafter, except for the above-mentioned a), the metal oxide fine particles and the above b) will be described.

(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. is there. The silica fine particles can be introduced into the film by adding colloidal silica, for example. The metal oxide fine particles have an excellent effect of transmitting the stress applied to the antifogging film to the transparent article supporting the film, and have high hardness. Therefore, the addition of the metal oxide fine particles is advantageous from the viewpoint of improving the wear resistance and scratch resistance of the antifogging film. Further, when the metal oxide fine particles are added to the antifogging film, fine voids are formed in a portion where the fine particles are in contact with or close to each other, and water vapor is easily taken into the film through the voids. For this reason, the addition of the metal oxide fine particles may act advantageously to improve the antifogging property. The metal oxide fine particles can be supplied to the antifogging film by adding the previously formed metal oxide fine particles to the coating liquid for forming the antifogging film.

If the average particle size of the metal oxide fine particles is too large, the film may become cloudy, and if it is too small, it becomes difficult to aggregate and uniformly disperse. From this viewpoint, the preferable average particle diameter of the metal oxide fine particles is 1 to 20 nm, particularly 5 to 20 nm. In addition, here, the average particle diameter of the metal oxide fine particles is described in the state of primary particles. The average particle size of the metal oxide particles is determined by measuring the particle size of 50 particles arbitrarily selected by observation using a scanning electron microscope and adopting the average value thereof. If the content of the metal oxide fine particles is excessively large, the water absorption amount of the entire film may decrease, and the film may become cloudy. When the antifogging film contains a water-absorbent resin, the metal oxide fine particles are 0 to 50 parts by mass, preferably 1 to 30 parts by mass, more preferably 2 to 30 parts by mass, particularly preferably 2 to 30 parts by mass, relative to 100 parts by mass of the water absorbent resin. It is preferable to add 5 to 25 parts by mass, and in some cases 10 to 20 parts by mass.

(Hydrolysable metal compound having no water repellent group)
Further, the antifogging film 9 may contain a metal oxide component derived from a hydrolyzable metal compound having no water-repellent group (hydrolyzable compound not containing a water-repellent group). A preferred water-repellent group-free hydrolyzable metal compound is a hydrolyzable silicon compound having no water-repellent group. The hydrolyzable silicon compound having no water repellent group is, for example, at least one silicon compound selected from silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane and aminosilane (provided that it has no water repellent group), Silicon alkoxide having no water repellent group is preferred. An example of alkenyloxysilane is isopropenoxysilane.

The hydrolyzable silicon compound having no water repellent group may be a compound represented by the following formula (III).
SiY ₄ (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 water-repellent group-free hydrolyzable metal compound is hydrolyzed or partially hydrolyzed, and at least a part thereof is polycondensed to supply a metal oxide component in which a metal atom and an oxygen atom are bonded. This component firmly joins the metal oxide fine particles and the water-absorbent resin and can contribute to the improvement of the wear resistance, hardness, water resistance and the like of the antifogging film. When the antifogging film contains a water-absorbent resin, the metal oxide component derived from the hydrolyzable metal compound having no water-repellent group is 0 to 40 parts by mass, preferably 0. The range is 1 to 30 parts by mass, more preferably 1 to 20 parts by mass, particularly preferably 3 to 10 parts by mass, and in some cases 4 to 12 parts by mass.

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

If the content of the metal oxide (silica) component derived from tetraalkoxysilane is excessively large, the antifogging property of the antifogging film may decrease. This is partly because the flexibility of the anti-fog film is lowered and the swelling and contraction of the film due to absorption and release of water are limited. When the antifogging film contains a water absorbent resin, the metal oxide component derived from tetraalkoxysilane is 0 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 3 parts by mass with respect to 100 parts by mass of the water absorbent resin. It may be added in the range of 10 to 10 parts by mass.

Another preferable example of the hydrolyzable silicon compound having no water repellent group is a silane coupling agent. The silane coupling agent is a silicon compound having reactive functional groups different from each other. A part of the reactive functional group is preferably 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 preferable 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. Since the glycidyloxyalkyl group and the aminoalkyl group include a functional group having hydrophilicity (epoxy group, amino group), the glycidyloxyalkyl group and the aminoalkyl group include an alkylene group, but are not water-repellent as a whole.

The silane coupling agent firmly bonds the water absorbent resin as an organic component to the metal oxide fine particles as an inorganic component, and can contribute to the improvement of the wear resistance, hardness, water resistance and the like of the antifogging film. However, if the content of the metal oxide (silica) component derived from the silane coupling agent is excessively large, the antifogging property of the antifogging film is deteriorated and the antifogging film becomes cloudy in some cases. 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, relative to 100 parts by mass of the water absorbent resin. It is preferable to add it in the range 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 organic boron compounds, organic titanium compounds and organic zirconium compounds. The introduction of the crosslinked structure improves the abrasion resistance, scratch resistance and water resistance of the antifogging film. Stated from another point of view, the introduction of the crosslinked structure facilitates improving the durability of the antifogging film without deteriorating its antifogging performance.

When a crosslinked structure derived from a crosslinking agent is introduced into the antifogging film in which the metal oxide component is a silica component, the antifogging film is a metal atom other than silicon together with silicon as a metal atom, preferably boron, titanium or zirconium, May be included.

The type of the cross-linking agent is not particularly limited as long as it can cross-link the water absorbent resin used. Here, only the organic titanium compound will be described as an example. The organic titanium compound is, for example, at least one selected from titanium alkoxides, titanium chelate compounds and titanium acylates. The titanium alkoxide is, for example, titanium tetraisopropoxide, titanium tetra-n-butoxide, or titanium tetraoctoxide. Titanium chelate compounds are, for example, titanium acetylacetonate, ethyl titanium acetoacetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. The titanium lactate may be an ammonium salt (titanium lactate ammonium). Titanium acylate is, for example, titanium stearate. A preferred organotitanium compound is a titanium chelate compound, particularly titanium lactate.

When the water absorbent resin is polyvinyl acetal, a preferable crosslinking agent is an organic titanium compound, particularly titanium lactate.

[Other optional ingredients]
Other additives may be added to the antifogging film 9. Examples of the additive include glycols such as glycerin and ethylene glycol having a function of improving antifogging property. The additive may be a surfactant, a leveling agent, an ultraviolet absorber, a coloring agent, a defoaming agent, a preservative, or the like.

[Film thickness]
The film thickness of the anti-fogging film 9 may be appropriately adjusted according to the required anti-fogging property and the like. The preferable film thickness of the antifogging film 9 is 1 to 20 μm, preferably 2 to 15 μm, and particularly 3 to 10 μm.

[Film formation]
The antifogging film 9 is formed by applying a coating solution for forming the antifogging film 9 onto a transparent article such as a transparent substrate, drying the applied coating solution, and further subjecting it to a high temperature and high humidity treatment or the like. A film can be formed by carrying out. As the solvent used for preparing the coating liquid and the coating method of the coating liquid, conventionally known materials and methods may be used.

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

The coating liquid drying step preferably includes an air drying step and a heating and drying step involving heating. The air-drying step is preferably performed by exposing the coating liquid to an atmosphere in which the relative humidity is kept at less than 40%, further 30% or less. The air drying step can be performed as a non-heating step, in other words, at room temperature. When the coating liquid contains a hydrolyzable silicon compound, in the heating and drying step, the dehydration reaction involving the silanol group contained in the hydrolyzate of the silicon compound and the hydroxyl group present on the transparent article proceeds, A matrix structure (Si—O bond network) composed of silicon atoms and oxygen atoms develops.

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

When forming the anti-fog film 9, a high temperature and high humidity treatment step may be appropriately performed. By carrying out the high-temperature and high-humidity treatment step, both antifogging property and film strength can be made easier together. The high-temperature and high-humidity treatment step can be carried out, for example, by holding in an atmosphere of 50 to 100° C. and a relative humidity of 60 to 95% for 5 minutes to 1 hour. The high temperature and high humidity treatment step may be performed after the coating step and the drying step, or after the coating step and the air drying step and before the heating and 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 carried out, for example, by holding in an atmosphere of 80 to 180° C. for 5 minutes to 1 hour.

In addition, the antifogging film 9 formed from the coating liquid may be washed and/or wiped with a compress if necessary. Specifically, it can be carried out by exposing the surface of the antifogging film 9 to a stream of water or wiping it with a cloth moistened with water. Pure water is suitable for the water used in these. Avoid using solutions containing detergents for cleaning. By this step, dust, dirt and the like adhering to the surface of the antifogging film 9 can be removed and a clean coating film surface can be obtained.

As is clear from the above description, the following are preferred forms of the antifogging film 9. That is, the antifogging film 9 preferably contains 0.1 to 60 parts by mass of the metal oxide component and 0.05 to 10 parts by mass of the water repellent group with respect to 100 parts by mass of the water absorbent resin. At this time, the water-repellent group is a chain alkyl group having 1 to 8 carbon atoms, the water-repellent group is directly bonded to the metal atom constituting the metal oxide component, and the metal atom may be silicon. .. Further, at least a part of the metal oxide component is added to the coating liquid for forming the antifogging film, the metal oxide component derived from the hydrolyzable metal compound or the hydrolyzate of the hydrolyzable metal compound. 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 having no water repellent group. Further, the hydrolyzable metal compound having no water-repellent group may contain at least one selected from tetraalkoxysilane and silane coupling agents. By making the anti-fog film 9 in this way, it is possible to suppress the fogging of the information acquisition area 23, and it becomes possible to appropriately acquire the information outside the vehicle by the information acquisition device. When the antifogging film 9 is arranged on the fourth surface 222, the information acquisition region heating unit 5 should be prevented from coming into direct contact with the antifogging film 9, for example, as in the above embodiment, the information acquisition region heating unit. It is desirable to dispose 5 on a surface other than the fourth surface 222. Thereby, the deterioration of the antifogging film 9 can be prevented.

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

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

That is, the information acquisition region 23D is a region where the ceramic forming the shielding layer 3D is not partially applied, and thus the information acquisition region 23D can be provided in the protruding region 32. The photographing device 8 can photograph the situation outside the vehicle through the information acquisition area 23D.

In this modification, the shielding layer 3D is provided all around the information acquisition area 23D. However, the shape of the shielding layer 3D does not have to be limited to such an example, and at least one of the left and right sides and the lower side of the information acquisition area 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 above embodiment, the image capturing device 8 is used as the information acquisition device. However, the information acquisition device is not limited to such an example as long as it is a device that can acquire information from outside the vehicle by irradiating and/or receiving light, and the information acquisition device can be appropriately changed according to the embodiment. May be selected. For example, as the information acquisition device, visible light and/or infrared camera for measuring the inter-vehicle distance, a light receiving device that receives a signal from the outside of the vehicle such as an optical beacon, and a visible light that reads a white line of the road in an image and/or Various devices such as a camera using infrared rays may be used.

Further, a plurality of information acquisition devices may be used, or a stereo camera including a plurality of image capturing devices may be used as the information acquisition device. A well-known stereo camera can be used. In this case, a plurality of information acquisition areas 23 can be provided corresponding to a plurality of information acquisition devices and/or a plurality of imaging devices. Further, the information acquisition area heating 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. Further, one information acquisition area heating unit 5 may be provided so as to include two or more information acquisition areas 23. The number and arrangement of the information acquisition areas 23 and the number and arrangement of the information acquisition area heating units 5 may be appropriately selected according to the embodiment.

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

<3.7>
Further, for example, in the above embodiment, the shielding layer 3 is laminated on the fourth surface 222 of the laminated glass 2. However, the surface on which the shielding layer 3 is laminated is not limited to such an example, and may be appropriately selected according to the embodiment. For example, the shielding layer 3 may be laminated on the second 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 gravity bending. However, the method of forming the laminated glass 2 is not limited to such an example, and may be appropriately selected according to the embodiment. For example, the laminated glass 2 may be formed into a curved shape by known press molding.

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

<3.10>
Further, for example, in the above embodiment, the shielding layer 3 has a single layer structure. However, the shielding layer 3 may have a multi-layer structure. For example, the first ceramic layer is formed by laminating a 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 a ceramic on this silver layer. Thereby, the shield layer 3 having a three-layer structure can be formed. The shielding layer 3 having the three-layer structure can shield electromagnetic waves by the silver layer. In addition, the material having the composition shown in Table 2 below can be used for this silver layer.

*1, Main component: Bismuth borosilicate, zinc borosilicate

<3.11>
Further, for example, in the above embodiment, each heating wire 52A to 52C is formed in a substantially U-shape. However, the shape of each of the heating wires 52A to 52C may not be limited to such an example, and may be appropriately formed so as to pass through the information acquisition area 23 and be connectable to both bus bar portions 51. That is, if the shape of each heating wire 52A to 52C is a shape that extends inward in the plane direction from one bus bar portion 51, passes through the information acquisition region 23, is folded back and extends toward the other bus bar portion 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 unit 5E according to this modification. The information acquisition area heating unit 5E includes two heating wires (54A, 54B) arranged in parallel. The first heating wire 54A is arranged outside and the second heating wire 54B is arranged inside. Both heating wires (54A, 54B) both extend from one bus bar portion 51 toward the information acquisition area 23 and pass through the information acquisition area 23, and are folded back near the center extending toward the other bus bar portion 51, Each bus bar portion 51 has a folded-back portion (541A, 541B) that is folded back. Thus, each heating wire may include a fold back portion. As a result, even if the number of heating wires is small, the information acquisition area 23 can be uniformly heated.

In this modification, the cross-sectional areas of both heating wires (54A, 54B) may be the same. However, the first heating wire 54A arranged on the outer side is longer than the second heating wire 54B arranged on the inner side. Therefore, from the relational expressions of the above equations 1 to 3, there is a possibility that the heat generation amount of the first heating wire 54A arranged 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 the heating values of both heating wires (54A, 54B) are substantially the same.

1... Windshield,
2... laminated glass,
21... Outer glass plate, 211... First surface, 212... Second surface,
22... inner glass plate, 221... 3rd surface, 222... 4th surface, 223-226... notch,
23... Information acquisition area,
3... Shielding layer, 31... Strip area,
4... Intermediate layer, 41... Base material, 42...43... Adhesive layer,
5... Information acquisition area heating unit, 51... Bus bar unit, 52A to 52C... Heating wire,
6... Other area heating part, 61... Bus bar part, 62... Heating wire,
71... Connecting material, 72... Fixing material, 73... Connecting material, 74... Fixing material,
8... Imaging device, 81... Image processing device,
9... Anti-fog film,
11... Release film, 12... Adhesive layer

Claims (10)

A windshield of an automobile in which an information acquisition device that acquires information from outside the vehicle by irradiating and/or receiving light can be arranged.
A glass plate having an information acquisition region facing the information acquisition device and through which the light passes,
A shielding layer provided on the glass plate and shielding a field of view from outside the vehicle,
An information acquisition region heating unit that has a pair of bus bar units and a plurality of heating wires, and heats the information acquisition region,
Equipped with
The shielding layer includes a strip-shaped region extending along an edge of the glass plate,
The information acquisition region is arranged adjacent to the inner side in the plane direction of the strip-shaped region,
Both bus bar portions of the information acquisition region heating unit are arranged side by side so as to be included in the strip-shaped region in the viewing direction,
Each heating wire of the information acquisition region heating unit is connected in parallel to the both bus bar units, extends inward in the plane direction from one bus bar unit and passes over the information acquisition region, and is folded back to the other bus bar unit. Extending toward the
Windshield. In the plurality of heating wires, the heating wire extending inward in the plane direction has a larger cross-sectional area.
The windshield according to claim 1. At least one of adjacent heating wires of the plurality of heating wires has a portion extending in parallel with each other,
The parallel extending portions of the heating wires adjacent to each other are each formed in a wavy shape,
The windshield according to claim 1. The wavy patterns of the parallel extending portions of the adjacent heating wires are displaced from each other,
The windshield according to claim 3. An anti-fog film is attached to the information acquisition area,
The windshield according to any one of claims 1 to 4. The plurality of heating wires are formed of copper,
The windshield according to any one of claims 1 to 5. Having one or a plurality of heating wires, further comprising another area heating unit for heating an area other than the information acquisition area,
The windshield according to any one of claims 1 to 6. The heat generation amount per unit area of the information acquisition region heating unit is different from the heat generation amount per unit area of the other region heating unit,
The windshield according to claim 7. The cross-sectional area of each heating wire of the information acquisition area heating unit is larger than the heating wire of the other area heating unit,
The windshield according to claim 8. The cross-sectional area of each heating wire of the information acquisition area heating unit is smaller than the heating wire of the other area heating unit,
The windshield according to claim 8.