Patent Description:
<CIT> discloses a connection terminal to be connected to a conductive electricity supply portion formed on a glass plate of an automobile. A heating wire of a defogger or the like, or an antenna conductor is to be connected to this electricity supply portion. A wire such as a cable is connected to the connection terminal. Electricity is supplied from the electricity supply portion via the connection terminal, and thereby the heating wire heats the glass plate, or the antenna conductor receives electric power from the electricity supply portion and thus receives a radio wave. <CIT> concerns a pane with an illuminated switch surface and a heating function. <CIT> concerns a windowpane for vehicles including a glass sheet, a conductor layer which is formed on the surface of the glass sheet by sintering a silver paste containing a silver powder and a glass frit and which has at least a strip part and a terminal connection part connected to the strip part, and a connection terminal soldered onto the terminal connection part with a lead-free solder alloy, in which the conductor layer has a specific resistance of from <NUM> to <NUM>µΩcm, the strip part has a line width of not more than <NUM>, the lead-free solder alloy consists essentially of tin and silver and has a content of tin of <NUM>% by mass or more, and cracking is not caused on the glass sheet even after elapsing <NUM> cycles in a prescribed thermal shock test.

The connection terminal as mentioned above is fixed to the electricity supply portion via solder. However, if an external force acts on the connection terminal, the electricity supply portion or the glass plate may crack.

The present invention was made in order to solve the aforementioned problem, and it is an object thereof to provide a glass plate module in which a connection terminal or a wire is fixed to an electricity supply portion and that is capable of suppressing the generation of cracks in the glass plate or the electricity supply portion even if an external force acts on the connection terminal or wire.

With the present invention, generation of cracks in the electricity supply portion or glass plate can be suppressed.

First, the configuration of a windshield according to this embodiment will be described with reference to <FIG> and <FIG>. <FIG> is a plan view of the windshield, and <FIG> is a cross-sectional view of <FIG>. Note that, for the convenience of description, the "up-down direction" in <FIG> refers to "upper and lower", "perpendicular", and "vertical", and the "left-right direction" in <FIG> refers to "horizontal". <FIG> illustrates the windshield as viewed from the vehicle interior side. That is, the back side of the sheet of <FIG> corresponds to the vehicle exterior side, and the front side of the sheet of <FIG> corresponds to the vehicle interior side.

This windshield includes substantially rectangular laminated glass <NUM>, and is installed in a vehicle body in an inclined state. An inner surface <NUM> of this laminated glass <NUM> that faces the vehicle interior side is provided with a mask layer <NUM> that blocks the field of view from the outside of the vehicle, and an imaging device <NUM> is disposed such that the mask layer <NUM> conceals the imaging device <NUM> from the outside of the vehicle. However, the imaging device <NUM> is a camera for taking images of the outside of the vehicle. Thus, the mask layer <NUM> is provided with an imaging window (opening) <NUM> at a position corresponding to the imaging device <NUM>, and the imaging device <NUM> disposed inside the vehicle can take images of the outside of the vehicle through the imaging window <NUM>.

An image processing device <NUM> is connected to the imaging device <NUM>, and the image processing device <NUM> processes images taken by the imaging device <NUM>. The imaging device <NUM> and the image processing device <NUM> are included in an in-vehicle system <NUM>, and the in-vehicle system <NUM> can provide various pieces of information to a passenger in accordance with processing performed by the image processing device <NUM>.

Also, as described later, a heating body <NUM> is disposed on the surface on the vehicle interior side of the windshield in a region corresponding to the imaging window <NUM>, and the windshield is configured to prevent the region of the windshield that corresponds to the imaging window <NUM> from fogging up and to defrost this region. Hereinafter, these constituent elements will be described.

<FIG> is a cross-sectional view of laminated glass. As shown in <FIG>, this laminated glass <NUM> includes an outer glass plate <NUM> and an inner glass plate <NUM>, and a resin interlayer <NUM> is disposed between the glass plates <NUM> and <NUM>. Hereinafter, the configurations thereof will be described.

First, the outer glass plate <NUM> and the inner glass plate <NUM> will be described. Known glass plates can be used as the outer glass plate <NUM> and the inner glass plate <NUM>, and these glass plates can also be made of heat-ray absorbing glass, regular clear glass or green glass, or UV green glass. However, the glass plates <NUM> and <NUM> are required to have a visible light transmittance that conforms to the safety standards of a country in which the automobile is to be used. For example, adjustments can be made so that solar absorptance that the outer glass plate <NUM> is required to have is ensured and the inner glass plate <NUM> provides a visible light transmittance that meets the safety standards. An example of clear glass, an example of heat-ray absorbing glass, and an example of soda-lime based glass are shown below.

With regard to the composition of heat-ray absorbing glass, a composition obtained based on the composition of clear glass by setting the ratio of the total iron oxide (T-Fe<NUM>O<NUM>) in terms of Fe<NUM>O<NUM> to <NUM> to <NUM> mass%, the ratio of CeO<NUM> to <NUM> to <NUM> mass%, and the ratio of TiO<NUM> to <NUM> to <NUM> mass%, and reducing the components (mainly SiO<NUM> and Al<NUM>O<NUM>) forming the framework of glass by an amount corresponding to increases in T-Fe<NUM>O<NUM>, CeO<NUM>, and TiO<NUM> can be used, for example.

Although there is no particular limitation on the thickness of the laminated glass according to this embodiment, it is possible to set the total thickness of the outer glass plate <NUM> and the inner glass plate <NUM> to, for example, <NUM> to <NUM>, and the total thickness of the outer glass plate <NUM> and the inner glass plate <NUM> is preferably set to <NUM> to <NUM>, more preferably <NUM> to <NUM>, and particularly preferably <NUM> to <NUM>, from the viewpoint of weight reduction. As described above, there is a need to reduce the total thickness of the outer glass plate <NUM> and the inner glass plate <NUM> in order to achieve weight reduction. Therefore, although there is no particular limitation on the thicknesses of the glass plates, the thicknesses of the outer glass plate <NUM> and the inner glass plate <NUM> can be determined as described below, for example.

The outer glass plate <NUM> is mainly required to have durability and impact resistance against external hazards. When this laminated glass is used as, for example, a windshield of an automobile, impact-resistance against flying objects such as small stones is required. On the other hand, a larger thickness is not preferable because the weight increases. From this viewpoint, the thickness of the outer glass plate <NUM> is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>. The thickness to be used can be determined in accordance with the application of the glass plate.

Although the thickness of the inner glass plate <NUM> can be made equal to that of the outer glass plate <NUM>, the thickness of the inner glass plate <NUM> can be made smaller than that of the outer glass plate <NUM> in order to, for example, reduce the weight of the laminated glass. Specifically, when the strength of the glass plate is taken into consideration, the thickness is preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, and particularly preferably <NUM> to <NUM>. Furthermore, the thickness is preferably <NUM> to <NUM>. With regard to the inner glass plate <NUM> as well, the thickness to be used can be determined in accordance with the application of the glass plate.

Here, an example of a method of measuring the thickness of a curved glass plate (laminated glass) <NUM> will be described. First, with respect to the measurement position, the measurement is performed at two positions: an upper position and a lower position on a center line S extending vertically through the center of a glass plate in the horizontal direction. Although there is no particular limitation on the measuring apparatus, a thickness gauge such as SM-<NUM> manufactured by TECLOCK Corporation can be used, for example. During measurement, the glass plate is disposed such that the curved surface of the glass plate is placed on a flat surface, and an end portion of the glass plate is sandwiched by and measured with the above-mentioned thickness gauge. Note that a flat glass plate can also be measured in the same manner as a curved glass plate.

As described later, the laminated glass <NUM> is provided with electricity supply portions <NUM> and <NUM> for supplying electricity to the heating body <NUM>. At least a <NUM>-mm<NUM> region is needed to attach a connection terminal or wire to each of these electricity supply portions <NUM> and <NUM>. Since a force is applied to the wire, it is preferable that the glass plate has sufficient fracture strength such that the glass does not break when this region is subjected to a force of <NUM> N. This is based on a German automobile specification test (Test Specification of the AK2. <NUM> of German Car Manufacturer).

Specifically, when the thickness of the outer glass plate <NUM> or inner glass plate <NUM> included in the laminated glass that is provided with the electricity supply portions <NUM> and <NUM> is defined as Dx (mm), it is preferable that fracture strength H (MPa) of this glass plate satisfies the following formula.

The interlayer <NUM> includes at least one layer. For example, as shown in <FIG>, the interlayer <NUM> can be configured by three layers, namely a soft core layer <NUM> and outer layers <NUM> that are harder than the core layer <NUM> and between which the core layer <NUM> is held. However, there is no limitation to this configuration, and it is sufficient that the interlayer <NUM> includes a plurality of layers including the core layer <NUM> and at least one outer layer <NUM> disposed on the outer glass plate <NUM> side. For example, the interlayer <NUM> that includes two layers, namely the core layer <NUM> and one outer layer <NUM> disposed on the outer glass plate <NUM> side, or the interlayer <NUM> in which an even number of two or more of the outer layers <NUM> are disposed on each side of the core layer <NUM> so that the core layer <NUM> is disposed at the center, or the interlayer <NUM> in which an odd number of outer layers <NUM> are disposed on one side of the core layer <NUM> and an even number of outer layers <NUM> are disposed on the other side so that the core layer <NUM> is located therebetween can also be formed. Note that, in the case where only one outer layer <NUM> is provided, the outer layer <NUM> is provided on the outer glass plate <NUM> side as mentioned above, which is for the purpose of improving the breakage resistance against an external force from the outside of a vehicle or a building. Also, when the number of outer layers <NUM> is increased, the sound insulation performance is improved.

There is no particular limitation on the hardness of the core layer <NUM> as long as the core layer <NUM> is softer than the outer layer <NUM>. Although there is no particular limitation on the materials constituting the layers <NUM> and <NUM>, it is possible to select materials based on, for example, the Young's modulus. Specifically, at a frequency of <NUM> and a temperature of <NUM>, the Young's modulus is preferably <NUM> to <NUM> MPa, more preferably <NUM> to <NUM> MPa, and particularly preferably <NUM> to <NUM> MPa. When the Young's modulus is set to be in such a range, it is possible to prevent a decrease in STL in a low frequency range of about <NUM> or lower. On the other hand, as will be described later, it is preferable that the outer layers <NUM> have a large Young's modulus for the purpose of improving the sound insulation performance in a high frequency range, and the Young's modulus can be set to <NUM> MPa or more, <NUM> MPa or more, <NUM> MPa or more, <NUM> MPa or more, <NUM> MPa or more, <NUM> MPa or more, or <NUM> MPa or more at a frequency of <NUM> and a temperature of <NUM>. Meanwhile, there is no particular limitation on the upper limit of the Young's modulus of each of the outer layers <NUM>, but the Young's modulus can be set from the viewpoint of, for example, workability. For example, it is empirically known that when the Young's modulus is set to <NUM> MPa or more, the workability decreases, and cutting becomes particularly difficult.

Also, the outer layers <NUM> can be made of, for example, a polyvinyl butyral resin (PVB) as a specific material. A polyvinyl butyral resin has excellent adhesiveness to the glass plates and penetration resistance and is thus preferable. On the other hand, the core layer <NUM> can be made of an ethylene vinyl acetate resin (EVA) or a polyvinyl acetal resin, which is softer than the polyvinyl butyral resin constituting the outer layers. Arranging the soft core layer between the outer layers makes it possible to significantly improve the sound insulation performance while keeping adhesiveness and penetration resistance that are equivalent to those of a single-layered resin interlayer.

In general, the hardness of a polyvinyl acetal resin can be controlled by adjusting (a) the degree of polymerization of polyvinyl alcohol, which is the starting material, (b) the degree of acetalization, (c) the type of plasticizer, (d) the ratio of the plasticizer to be added, and the like. Accordingly, a hard polyvinyl butyral resin that is used for the outer layers <NUM> and a soft polyvinyl butyral resin that is used for the core layer <NUM> can be produced with the same polyvinyl butyral resin by appropriately adjusting at least one condition selected from the aforementioned conditions. Furthermore, the hardness of a polyvinyl acetal resin can be controlled based on the type of aldehyde that is used for acetalization and whether co-acetalization using a plurality of kinds of aldehydes or pure acetalization using a single kind of aldehyde is performed. Although not necessarily applicable to every case, the larger the number of carbon atoms of the aldehyde that is used to obtain a polyvinyl acetal resin, the softer the resulting polyvinyl acetal resin tends to be. Accordingly, for example, if the outer layers <NUM> are made of a polyvinyl butyral resin, a polyvinyl acetal resin that is obtained by acetalizing an aldehyde having <NUM> or more carbon atoms (e.g. , n-hexyl aldehyde, <NUM>-ethylbutyl aldehyde, n-heptyl aldehyde, or n-octyl aldehyde) with polyvinyl alcohol can be used for the core layer <NUM>. Note that there is no limitation to the above-mentioned resins and the like as long as predetermined Young's moduli can be obtained.

The total thickness of the interlayer <NUM> is not particularly specified, and is preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, and particularly preferably <NUM> to <NUM>. Also, the thickness of the core layer <NUM> is preferably <NUM> to <NUM> and more preferably <NUM> to <NUM>. Meanwhile, the thickness of each of the outer layers <NUM> is preferably <NUM> to <NUM> and more preferably <NUM> to <NUM>. Alternatively, it is also possible to fix the total thickness of the interlayer <NUM> and adjust the thickness of the core layer <NUM> without exceeding the fixed total thickness.

The thicknesses of the core layer <NUM> and the outer layers <NUM> can be measured, for example, as described below. First, a cross section of laminated glass is displayed enlarged by a factor of <NUM> using a microscope (e.g., VH-<NUM> manufactured by Keyence Corporation). Then, the thicknesses of the core layer <NUM> and the outer layers <NUM> are visually identified and measured. At this time, in order to eliminate variations seen in visual identification, the measurement is performed five times, and average values are taken as the thicknesses of the core layer <NUM> and the outer layers <NUM>. For example, an enlarged photograph of laminated glass is taken, in which the core layer and the outer layers <NUM> are identified and the thicknesses thereof are measured.

Note that the core layer <NUM> and the outer layers <NUM> of the interlayer <NUM> are not required to have a constant thickness along the entire surface of the laminated glass. For example, the core layer <NUM> and the outer layers <NUM> can also have a wedge shape so as to be suited to a laminated glass that is used for a head-up display. In this case, the thicknesses of the core layer <NUM> and the outer layers <NUM> of the interlayer <NUM> are measured at positions having the smallest thickness, that is, in the lowest side portion of the laminated glass. If the interlayer <NUM> has a wedge shape, the outer glass plate and the inner glass plate are not disposed in parallel, but it should be construed that such an arrangement is also included in the arrangement of the glass plates of the present invention. That is, the arrangement according to the present invention includes, for example, the arrangement of the outer glass plate and the inner glass plate when the interlayer <NUM> that includes the core layer <NUM> and the outer layers <NUM> whose thicknesses increase at a rate of change of <NUM> or less per meter is used.

Although there is no particular limitation on the method of manufacturing the interlayer <NUM>, examples thereof include a method in which a resin component, such as the above-described polyvinyl acetal resin, a plasticizer, and other additives, if necessary, are mixed and uniformly kneaded, and then the layers are collectively extruded, and a method in which two or more resin films that are produced using this method are laminated using a pressing process, a lamination process, or the like. In the method of laminating using the pressing process, the lamination process, or the like, each of the resin films before laminating may have a single-layer structure or a multilayer structure. Also, the interlayer <NUM> may include a single layer instead of the plurality of layers as mentioned above.

Next, the mask layer <NUM> will be described. As illustrated in <FIG> and <FIG>, in this embodiment, the mask layer <NUM> is layered on an inner surface (an inner surface of the inner glass plate <NUM>) <NUM> on the vehicle interior side of the laminated glass <NUM>, and is formed along a peripheral edge portion of the laminated glass <NUM>. Specifically, as illustrated in <FIG>, the mask layer <NUM> according to this embodiment includes a peripheral edge region <NUM> extending along the peripheral edge portion of the laminated glass <NUM>, and a protruding region <NUM> that protrudes downward from the upper side of the laminated glass <NUM> in a rectangular shape. The peripheral edge region <NUM> blocks light entering from the peripheral edge portion of the windshield. On the other hand, the protruding region <NUM> conceals the imaging device <NUM> disposed inside the vehicle from the outside of the vehicle.

However, if the mask layer <NUM> blocks the imaging range of the imaging device <NUM>, the imaging device <NUM> cannot take images of situation forward of the vehicle exterior. Thus, in this embodiment, the protruding region <NUM> of the mask layer <NUM> is provided with a trapezoidal imaging window <NUM> at a position corresponding to the imaging device <NUM> such that the imaging device <NUM> can take images of the outside of the vehicle. That is to say, the imaging window <NUM> is provided independently of a non-blocking region <NUM> on the inner side in the in-plane direction with respect to the mask layer <NUM>. Also, this imaging window <NUM> is a region where the material of the mask layer <NUM> is not layered, and thus it is possible to take images of the outside of the vehicle due to the laminated glass having the above-described visible light transmittance. Note that the size of the imaging window <NUM> is not particularly limited, and may be set to, for example, <NUM><NUM> or more.

As described above, the mask layer <NUM> may also be layered on an inner surface of the outer glass plate <NUM> and an outer surface of the inner glass plate <NUM>, for example, in addition to being layered on the inner surface of the inner glass plate <NUM>. Also, the mask layer <NUM> can be layered on two portions of the inner surface of the outer glass plate <NUM> and the inner surface of the inner glass plate <NUM>.

Next, the material of the mask layer <NUM> will be described. The material of the mask layer <NUM> may be selected as appropriate according to embodiments as long as it can block the field of view from the outside of the vehicle, and a ceramic material with a dark color such as black, brown, gray, or dark blue may be used, for example.

If a black ceramic material is selected as the material of the mask layer <NUM>, for example, the black ceramic material is layered on the peripheral edge portion of the inner surface <NUM> of the inner glass plate <NUM> through screen printing or the like, and the layered ceramic materials are heated together with the inner glass plate <NUM>. Thus, it is possible to form the mask layer <NUM> on the peripheral edge portion of the inner glass plate <NUM>. Also, when a black ceramic material is printed, a region where the black ceramic material is not partially printed is provided. Accordingly, it is possible to form the imaging window <NUM>. Note that various materials can be used as the ceramic material used for the mask layer <NUM>. For example, it is possible to use a ceramic material with a composition shown in Table <NUM> below for the mask layer <NUM>.

Next, an in-vehicle system <NUM> provided with the imaging device (the information acquisition device) <NUM> and the image processing device <NUM> will be described with reference to <FIG> illustrates the configuration of the in-vehicle system <NUM>. As illustrated in <FIG>, the in-vehicle system <NUM> according to this embodiment includes the above-mentioned imaging device <NUM> and the above-mentioned image processing device <NUM> connected to the imaging device <NUM>.

The image processing device <NUM> is a device for processing images taken by the imaging device <NUM>. This image processing device <NUM> includes, for example, general hardware such as a storage unit <NUM>, a control unit <NUM>, and an input/output unit <NUM> that are connected via a busbar, as a hardware configuration. However, the hardware configuration of the image processing device <NUM> is not limited to such an example, and, with regard to a specific hardware configuration of the image processing device <NUM>, it is possible to add, or omit and add constituent elements as appropriate according to an embodiment.

The storage unit <NUM> stores various data and programs used in processing executed by the control unit <NUM> (not shown). The storage unit <NUM> may be realized by, for example, a hard disk, or a recording medium such as a USB memory. Also, various data and programs stored in the storage unit <NUM> may be acquired from a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc). Furthermore, the storage unit <NUM> may be referred to as an "auxiliary storage".

As described above, the laminated glass <NUM> is disposed in an inclined orientation with respect to the vertical direction, and is curved. Also, the imaging device <NUM> takes images of the outside of a vehicle via such a laminated glass <NUM>. Thus, the images taken by the imaging device <NUM> are deformed according to the orientation, shape, refractive index, optical defects, and the like of the laminated glass <NUM>. Aberrations that are specific to the camera lens of the imaging device <NUM> also cause deformation. In view of this, the storage unit <NUM> may store correction data for correcting images that are deformed due to aberrations of the laminated glass <NUM> and the camera lens.

The control unit <NUM> includes one or more processors such as a microprocessor or a CPU (Central Processing Unit), and peripheral circuits (a ROM (Read Only Memory), a RAM (Random Access Memory), an interface circuit, and the like) used for processing performed by these processors. The ROM, the RAM, and the like may be called the main storages in the sense that they are located in the address space handled by the processors in the control unit <NUM>. The control unit <NUM> functions as an image processing unit <NUM> by executing various data and programs stored in the storage unit <NUM>.

The image processing unit <NUM> processes images taken by the imaging device <NUM>. Processing performed on the captured images can be selected as appropriate according to an embodiment. For example, the image processing unit <NUM> may recognize a subject present in a captured image by analyzing the captured image through pattern matching or the like. In this embodiment, since the imaging device <NUM> takes images of situation forward of the vehicle, the image processing unit <NUM> may further determine whether or not an organism such as a human being is present on the front side of the vehicle based on this subject recognition. Then, if a person is present on the front side of the vehicle, the image processing unit <NUM> may output a warning message, using a predetermined method. Also, the image processing unit <NUM> may perform a predetermined process on a captured image, for example. Then, the image processing unit <NUM> may output the processed captured image to a display device (not shown) such as a display connected to the image processing device <NUM>.

The input/output unit <NUM> is one or more interfaces for transmitting and receiving data to/from a device that is present outside the image processing device <NUM>. The input/output unit <NUM> is, for example, an interface for connecting to a user interface, or an interface of a USB (Universal Serial Bus). Note that, in this embodiment, the image processing device <NUM> is connected to the imaging device <NUM> via the input/output unit <NUM>, and acquires images taken by the imaging device <NUM>.

In addition to a device designed exclusively for a service to be provided, a general-purpose device such as a PC (Personal Computer) or a tablet terminal may be used as such an image processing device <NUM>.

Also, the above-mentioned imaging device <NUM> is attached to a bracket (not shown), and the bracket is attached to the mask layer <NUM>. Therefore, attachment of the imaging device <NUM> to the bracket and attachment of the bracket to the mask layer <NUM> are adjusted such that the optical axis of the camera of the imaging device <NUM> passes through the imaging window <NUM> in this state. Also, a cover (not shown) is attached to the bracket so as to cover the imaging device <NUM>. Therefore, the imaging device <NUM> is disposed in the space surrounded by the laminated glass <NUM>, the bracket, and the cover, and the imaging device <NUM> cannot be seen from the vehicle interior side, and only a portion of the imaging device <NUM> can be seen from the vehicle exterior side through the imaging window <NUM>. Also, the imaging device <NUM> and the above-described input/output unit <NUM> are connected to each other by a cable (not shown), and this cable is drawn out from the cover and is connected to the image processing device <NUM> disposed at a predetermined position in the vehicle.

Next, the heating body <NUM> will be described with reference to <FIG>. As shown in <FIG>, the heating body <NUM> is constituted by a first heating wire <NUM>, a second heating wire <NUM>, connection wires <NUM>, and two electricity supply portions <NUM> and <NUM>, and the first heating wire <NUM> and the second heating wire <NUM> are disposed on the surface on the vehicle interior side of the inner glass plate <NUM> so as to pass the imaging window <NUM>. More specifically, the first heating wire <NUM> and the second heating wire <NUM> are connected in parallel, and are disposed so as to pass the imaging window <NUM>. The first heating wire <NUM> is disposed so as to pass the upper portion of the imaging window <NUM>, and the second heating wire <NUM> is disposed so as to pass the lower portion of the imaging window <NUM>.

The first heating wire <NUM> is constituted by a combination of a plurality of main portions <NUM> that pass the imaging window <NUM> and are disposed in parallel, and a plurality of coupling portions <NUM> that are disposed outside the imaging window <NUM> and each couple the end portions of the adjacent main portions <NUM>. That is, the first heating wire <NUM> is a combination of the plurality of main portions <NUM> and the plurality of coupling portions <NUM>, and is thus disposed so as to pass the imaging window <NUM> a plurality of times. The interval between the adjacent main portions <NUM> is not particularly limited, and is preferably, for example, <NUM> or more, and more preferably <NUM> or more. In particular, the interval between the main portions <NUM> of the first heating wire <NUM> is preferably <NUM> times as large as the wire width. This configuration is for the purpose of balancing the wire width of the first heating wire <NUM> and the interval. For example, if the wire width is reduced, the resistance increases, and thus a sufficient amount of heat is not obtained at a certain electrical voltage. In addition, if the interval of the first heating wire <NUM> is reduced, the view from the imaging device <NUM> is blocked, which may affect the field of view.

The coupling portions <NUM> are each formed in a U-shape, but can also be formed in an overall curved shape. The reason for this is that, if the coupling portion <NUM> includes a sharp corner portion (bent portion), there is a risk that heat will be abnormally generated.

Both of the end portions of the first heating wire <NUM> are respectively coupled to a first electricity supply portion <NUM> and a second electricity supply portion <NUM> via the above-mentioned connection wires <NUM>. The electricity supply portions <NUM> and <NUM> are formed in a rectangular shape, and the terminals are fixed to the electricity supply portions <NUM> and <NUM> via solder, as will be described later. A source voltage of, for example, <NUM> to <NUM> V is applied to the terminals.

Although the first electricity supply portion <NUM> and the second electricity supply portion <NUM> are disposed at positions away from the imaging window <NUM>, both of them are disposed on the mask layer <NUM>. Also, the connection wires <NUM> are disposed on the mask layer <NUM>.

The second heating wire <NUM> has a configuration similar to that of the first heating wire <NUM>. That is, the second heating wire <NUM> is constituted by a combination of a plurality of main portions <NUM> that pass the imaging window <NUM> and are disposed in parallel, and a plurality of bent portions <NUM> that are disposed outside the imaging window <NUM> and each couple the end portions of the adjacent main portions <NUM>. Also, the second heating wire <NUM> is a combination of the plurality of main portions <NUM> and the plurality of bent portions <NUM>, and is thus disposed so as to pass the imaging window <NUM> a plurality of times. Note that the main portions <NUM> of the second heating wire <NUM> are disposed in parallel with the main portions <NUM> of the first heating wire <NUM>. Both of the end portions of the second heating wire <NUM> are respectively coupled to the first electricity supply portion <NUM> and the second electricity supply portion <NUM> via the above-mentioned connection wires <NUM>. Accordingly, the first heating wire <NUM> and the second heating wire <NUM> are connected to the two electricity supply portions <NUM> and <NUM> in the state of being parallel with each other, and each form a parallel circuit. For example, if the imaging window <NUM> has a large area, the lengths of the main portions <NUM> and <NUM> increase, and thus the amount of heat generated by the main portions may decrease. Therefore, when the heating body <NUM> includes a plurality of parallel circuits, the lengths of the first heating wire <NUM> and the second heating wire <NUM> decrease, thus making it possible to generate a sufficient amount of heat. Note that, if a constant electrical voltage is applied, a sufficient electrical current is allowed to flow by reducing the resistance. As a result, a sufficient amount of heat can be generated.

When the lengths of the connection wires <NUM> are increased, the resistance of these portions increases, and thus an amount of generated heat can be adjusted. That is, adjustment can be performed such that an amount of heat generated by the first and second heating wires <NUM> and <NUM> decreases.

The wire widths of the heating wires <NUM> and <NUM> are preferably, for example, <NUM> to <NUM>, and more preferably <NUM> to <NUM>. Furthermore, the wire widths are preferably <NUM> to <NUM>. The reason for this is that the smaller the wire width is, the harder it is to see the wires, and the more suitable for the imaging window <NUM> they are. In particular, it is preferable to set the wire widths of the main portions <NUM> and <NUM> of the heating wires <NUM> and <NUM> to be within the range above. On the other hand, wires with an excessively small thickness may be incapable of being manufactured. Moreover, if a constant electrical voltage is applied to a parallel circuit with an excessively small wire width, the resistance increases. As a result, an electrical current flowing in the circuit decreases, and thus sufficient heating cannot be performed. Note that the wire width as used herein means the wire width of the largest portion in the cross section of each heating wires <NUM> and <NUM>. For example, when the heating wires <NUM> and <NUM> have a trapezoidal cross section, the width of the lower side is taken as the wire width, and when the heating wires <NUM> and <NUM> have a circular cross section, the diameter is taken as the wire width. For example, the widths of the heating wires <NUM> and <NUM> can be measured in a state of being enlarged by a factor of <NUM> using a microscope such as VHX-<NUM> (manufactured by Keyence Corporation).

Also, the thicknesses of the heating wires <NUM> and <NUM> and the connection wires <NUM> are preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>. The reason for this is as follows: if the thickness is less than <NUM>, when the heating wires <NUM> and <NUM> and the connection wires <NUM> are printed on the mask layer <NUM>, for example, the mask layer <NUM> may absorb metal microparticles contained in the heating wires etc. <NUM> to <NUM>, as will be described later, and thus there is a possibility that the thicknesses of the heating wires etc. <NUM> to <NUM> change and uniform resistance cannot be obtained. On the other hand, if the thickness is more than <NUM>, the resistance becomes too small, and thus there is a possibility that local breakage occurs in the glass plate.

The heating wires <NUM> and <NUM>, the connection wires <NUM>, and the electricity supply portions <NUM> and <NUM> included in the heating body <NUM> are made of silver. The heating wires <NUM> and <NUM>, the connection wires <NUM>, and the electricity supply portions <NUM> and <NUM> are formed, for example, through printing such as screen printing. That is, the heating wires <NUM> and <NUM>, the connection wires <NUM>, and the electricity supply portions <NUM> and <NUM> are formed by applying a silver paste containing silver as metal microparticles through printing and then drying the paste. Note that, although the entire portion of the heating body <NUM> may be integrally formed through printing or the like, different materials can also be used to form the heating body <NUM>. For example, a configuration is also possible in which only the electricity supply portions <NUM> and <NUM> are formed using silver, whereas the heating wires <NUM> and <NUM> and the connection wires <NUM> are formed using a material different from silver. For example, the heating wires <NUM> and <NUM> and the connection wires <NUM> can be formed using a material containing various metal microparticles made of copper (or tin-plated copper), gold, aluminum, magnesium, cobalt, tungsten, and the like. In particular, it is preferable to use copper, gold, and aluminum, which are materials having an electric resistivity of <NUM>×<NUM>-<NUM> Qm or less, out of these metals.

When the electricity supply portions <NUM> and <NUM> contains silver metal microparticles, the electricity supply portions <NUM> and <NUM> formed using a silver paste preferably have a conductivity of <NUM>µΩ·cm or more and <NUM>Ω·cm or less, and more preferably <NUM>µΩ·cm or more and <NUM> Q-cm or less. Differences in heat shrinkage ratios in silver print largely depend on the silver content. Also, the resistivity depends on the silver content. Accordingly, the above-mentioned conductivity is preferable.

Next, the arrangement of terminals in the electricity supply portions <NUM> and <NUM> will be described. As shown in <FIG>, a terminal <NUM> is fixed to each of the electricity supply portions <NUM> and <NUM> via solder <NUM>. The terminal <NUM> includes a plate-like installation portion <NUM>, an upright portion <NUM> that stands upright from the end portion of the installation portion <NUM>, and an extension portion <NUM> that extends from the upper end of the upright portion <NUM> substantially in parallel with the installation portion <NUM>, and is formed in one piece using a plate-like conductive material. Plate-like fixation portions <NUM> are provided on both sides of the extension portion <NUM>, and a conductive cable <NUM> is crimped by these fixation portions <NUM>. Accordingly, electric power supplied through the conductive cables is supplied to the electricity supply portions <NUM> and <NUM> via the terminals <NUM> and the solder <NUM>, and thus the heating wires <NUM> and <NUM> generate heat.

The solder <NUM> may be lead-free solder or lead-containing solder, and lead-free solder is preferable. In the case of using lead-free solder, lead-free solder that contains Sn, for example, in an amount of <NUM>% or more is hard, and therefore, a laminated glass plate may crack if such lead-free solder is joined thereto. Even in such a case, it is sufficient that soft lead-free solder such as indium-based or bismuth-based lead-free solder is used and joined thereto. Note that, when lead-free solder is used, a force applied to a glass plate increases because the ductility of lead-free solder is lower than that of lead-containing solder. Accordingly, in the case of using lead-free solder, the glass plate is more likely to crack compared with the case of using lead-containing solder. Therefore, this embodiment exhibits a particularly large crack preventing effect when lead-free solder is used, as described later.

Although the electricity supply portions <NUM> and <NUM> are formed in a rectangular shape in this embodiment, there is no particular limitation on the shape thereof as long as they are larger than the installation portions <NUM> of the terminals <NUM>. Also, the electricity supply portions <NUM> and <NUM> are thinner than the heating wires <NUM> and <NUM> and the connection wires <NUM>. More specifically, the thicknesses of the electricity supply portions <NUM> and <NUM> are preferably, for example, <NUM> to <NUM>, and more preferably <NUM> to <NUM>. On the other hand, the heating wires <NUM> and <NUM> and the connection wires <NUM> are thicker than the electricity supply portions <NUM> and <NUM>, and the thicknesses thereof are preferably, for example, <NUM> to <NUM>, and more preferably <NUM> to <NUM>. Note that, the relationship between the electricity supply portions <NUM> and <NUM> and the heating wires <NUM> and <NUM>, which will be described below, can be applied to the relationship between the electricity supply portions <NUM> and <NUM> and the connection wires <NUM>.

If the thicknesses of the electricity supply portions <NUM> and <NUM> are less than <NUM>, there is a risk that the solder <NUM> absorbs silver microparticles, and thus joining to a connector or harness cannot be achieved. On the other hand, if the thicknesses of the electricity supply portions <NUM> and <NUM> are <NUM> or more, there is a risk that the fracture strength of glass will decrease due to tension stress caused by the heating wires <NUM> and <NUM> or the connection wires <NUM>, and thus fracture strength required for the glass cannot be obtained.

When the thicknesses of the electricity supply portions <NUM> and <NUM> are defined as D1, and the thicknesses of the connection wires <NUM> (or the heating wires <NUM> and <NUM>) are defined as D2, D1 is smaller than D2, and it is preferable that D1/D2 is <NUM> or more and <NUM> or less.

Furthermore, it is preferable that the relationship between the thicknesses D1 of the electricity supply portions <NUM> and <NUM> and a thickness Dx of the inner glass plate <NUM> or outer glass plate <NUM> on which the electricity supply portions <NUM> and <NUM> are provided satisfies Formula (<NUM>) below.

When the electricity supply portions <NUM> and <NUM> are formed through screen printing, a supporting portion <NUM> that supports the peripheral edge of a screen <NUM> is taller than the screen <NUM>, for example, as shown in <FIG>. Moreover, the screens <NUM> differ in height in accordance with the thicknesses of the electricity supply portions <NUM> and <NUM> and the heating wires <NUM> to <NUM>, which are different from each other. Accordingly, a squeegee <NUM> cannot sufficiently press the peripheral edge of the screen <NUM>, and therefore, the edge portions of the electricity supply portions <NUM> and <NUM> tend to be higher than the central portions thereof. Here, the central portion is a portion on which the installation portion <NUM> of the terminal <NUM> and the solder <NUM> are to be disposed, and the thickness of this portion corresponds to the above-described thicknesses of the electricity supply portions <NUM> and <NUM>, and is defined as D1 as described above. In addition, the thicknesses of the edge portions of the electricity supply portions <NUM> and <NUM> are referred to as D5. As mentioned above, the thicknesses D5 of the edge portions of the electricity supply portions <NUM> and <NUM> are larger than the thicknesses D1 of the central portions, and it is preferable that the relationship between the thicknesses D1 and D5 satisfy Formula (<NUM>) below.

Setting D1/D5 to <NUM> or more makes it possible to ensure the resistance of the terminal <NUM> and to suppress generation of heat by the terminal <NUM>. On the other hand, setting D1/D5 to <NUM> or less makes it possible to suppress tension stress caused by the difference in thermal expansion between silver and a glass plate.

The heating body <NUM> configured as mentioned above is covered by the bracket and the cover and cannot be thus seen from the inside of the vehicle. Also, the connection wires <NUM> and the electricity supply portions <NUM> and <NUM> are disposed on the mask layer <NUM> and cannot be thus seen from the outside of the vehicle as well. Note that the heating wire <NUM> need not be entirely covered by the bracket and the cover, and at least a portion thereof corresponding to the imaging window <NUM> may be covered by the bracket and the cover. Alternatively, only portions of the electricity supply portions <NUM> and <NUM> and the connection wires <NUM> may protrude from the bracket. However, in order to prevent the heating wire <NUM> from being touched from the inside of the vehicle, it is preferable that the entire heating wire <NUM> is entirely covered by the bracket and the cover. Note that, for example, even if a portion of the heating wire <NUM> protrudes from the bracket, it is sufficient that the portion is covered by the cover.

Next, a method for manufacturing a windshield will be described. First, the mask layer <NUM> is layered on at least one of the outer glass plate <NUM> and the inner glass plate <NUM> formed in predetermined shapes. Next, the above-described heating body <NUM> is formed through printing on a surface (including the mask layer <NUM>) on the vehicle interior side of the inner glass plate <NUM>. Then, these glass plates <NUM> and <NUM> are shaped to be curved. Although there is no particular limitation on the method therefor, known press-molding can be used, for example. Alternatively, once the outer glass plate <NUM> and the inner glass plate <NUM> have been placed on each other on a mold, the mold is heated by passing the mold through a heating furnace. Accordingly, the glass plates <NUM> and <NUM> can be curved under their own weight.

After the outer glass plate <NUM> and the inner glass plate <NUM> are molded in this manner, a laminate is formed in which the interlayer <NUM> is sandwiched between the outer glass plate <NUM> and the inner glass plate <NUM>. Note that the interlayer <NUM> is larger than the glass plates <NUM> and <NUM>.

Next, the laminate is placed into a rubber bag, and preliminarily bonding is carried out at about <NUM> to <NUM> under vacuum suction. Preliminary bonding can be carried out using a method other than this method, and the following method can also be adopted. For example, the above-mentioned laminate is heated in an oven at <NUM> to <NUM>. Subsequently, this laminate is pressed by a roll at <NUM> to <NUM> MPa. Then, the laminate is heated in an oven again at <NUM> to <NUM>, and is then pressed again by a roll at <NUM> to <NUM> MPa. Preliminary bonding is completed in this manner.

Then, permanent bonding is performed. The preliminarily bonded laminate is permanently bonded using an autoclave, for example, at a pressure of <NUM> to <NUM> atm and at <NUM> to <NUM>. Specifically, permanent bonding can be performed, for example, under the conditions of <NUM> atm of pressure and a temperature of <NUM>. The interlayer <NUM> is bonded to the glass plates <NUM> and <NUM> through preliminary bonding and permanent bonding described above. Then, a portion of the interlayer <NUM> that protrudes from the outer glass plate <NUM> and the inner glass plate <NUM> is cut off.

Thereafter, the terminals <NUM> are fixed to the electricity supply portions <NUM> and <NUM> using the solder <NUM>. A windshield is completed in this manner.

With the above-described windshield, it is possible to obtain the following effects.

Therefore, in this embodiment, tension stress generated in the glass plate <NUM> is reduced by setting the thicknesses of the electricity supply portions <NUM> and <NUM> to be smaller than those of the heating wires <NUM> and <NUM>, and thus the fracture strength of the glass plate <NUM> corresponding to the electricity supply portions <NUM> and <NUM> is improved. As a result, even if an external force acts on the electricity supply portions <NUM> and <NUM>, it is possible to suppress generation of cracks in the glass plate <NUM> or the electricity supply portions <NUM> and <NUM>.

In particular, regarding the relationship between the thicknesses D1 of the electricity supply portions <NUM> and <NUM> and the thicknesses D2 of the thinnest portions of the heating wires <NUM> and <NUM> (or connection wires <NUM>), D1/D2 is preferably <NUM> or more and <NUM> or less. The reason for this is as follows. Since the electricity supply portions <NUM> and <NUM> are wider than the heating wires <NUM> and <NUM>, the electric current density per unit width decreases, thus suppressing generation of heat. However, the electric current density increases at portions that are joined to the heating wires <NUM> and <NUM>. Therefore, if the value of D1/D2 is smaller than <NUM>, the difference in thickness at portions where the electricity supply portions <NUM> and <NUM> are joined to the heating wires <NUM> and <NUM> increases and thus heat is generated, which leads to energy loss. On the other hand, if D1/D2 is larger than <NUM>, the thicknesses of the electricity supply portions <NUM> and <NUM> are excessively large. Therefore, the fracture strength at the electricity supply portions <NUM> and <NUM> decreases as mentioned above, and thus the glass plate <NUM> may crack.

(<NUM>) Since the electricity supply portions <NUM> and <NUM> are wider than the heating wires <NUM> and <NUM> and the connection wires <NUM>, an amount of heat generated by the electricity supply portions <NUM> and <NUM>, which have no need to generate heat, can be reduced, and heat generated by the heating wires <NUM> and <NUM> can be increased, thus making it possible to heat the imaging window <NUM>.

Also, the electricity supply portions <NUM> and <NUM> are formed using conductive print that contains metal microparticles made of silver or the like. The heating body <NUM> that includes the electricity supply portions <NUM> and <NUM> is printed prior to molding of the glass plate, and adheres to the inner glass plate <NUM> during glass molding. However, when they are cooled to the ordinary temperature, thermal stress is generated at the interface between the heating body <NUM> and the inner glass plate <NUM> due to a difference in thermal expansion between the heating body <NUM> and the glass plate. As a result, the fracture strength of the inner glass plate <NUM> decreases at positions where the electricity supply portions <NUM> and <NUM> are formed.

As mentioned above, in this embodiment, the electricity supply portions <NUM> and <NUM> are thinner than the heating wires <NUM> and <NUM>. When the thicknesses d (D1 as described above) of the electricity supply portions <NUM> and <NUM> is reduced as shown in Formula (<NUM>) below, warping of the glass plate (<NUM>/RDTE) can be reduced, thus making it possible to reduce tension stress generated at the surface of the glass plate. As a result, it is possible to suppress a decrease in the fracture strength of the glass plate <NUM> at positions where the electricity supply portions <NUM> and <NUM> are formed. [Mathematical Formula <NUM>] <MAT> Ef: Young's modulus of silver, Es: Young's modulus of glass plate, νf: Poisson's ratio of silver, νs: Poisson's ratio of glass plate, d: Thickness of electricity supply portion, D: Thickness of glass plate, αf: Thermal expansion coefficient of silver, αs: Thermal expansion coefficient of glass plate, ΔT: Temperature difference between temperature at which electricity supply portion adheres and room temperature, <NUM>/RDTE: Curvature of interface between electricity supply portion and glass plate.

(<NUM>) It is necessary to decrease the wire widths of the heating wires <NUM> and <NUM> disposed on the imaging window <NUM> as mentioned above in order not to block the camera view, and to reduce the resistance thereof in order to secure a certain amount of generated heat. Therefore, it is necessary to increase the thicknesses of the heating wires <NUM> and <NUM>.

As described later, in the case of using the heating wires as deicers, it is also necessary to decrease the wire widths in order to secure an amount of heat generated per unit area, and to reduce the value of resistance in order to achieve sufficient heating using a certain electric current. Therefore, as in the case above, it is necessary to increase the thicknesses of the heating wires.

Furthermore, as described later, the antenna conductor preferably has a small wire width because a wide antenna conductor is likely to be visually confirmed by a passenger. However, it is necessary to increase the thickness of the antenna conductor in order to adjust the impedance of the antenna conductor.

However, when the heating wires <NUM> and <NUM>, the connection wires <NUM>, and the electricity supply portions <NUM> and <NUM> (referred to as "heating wires etc." hereinafter) are formed through screen printing, the thicknesses thereof cannot be changed because the thicknesses of the heating wires etc. to be printed are determined in accordance with the heights or thicknesses of screen meshes.

To address this, the inventor of the present invention found that, when narrow heating wires etc. are formed through screen printing, the thicknesses of the heating wires etc. can be controlled by controlling the thickness of an emulsion applied to the screen. That is, the thickness of the screen is controlled by applying an emulsion to the upper surface of the screen, and thus the thicknesses of the heating wires etc. are controlled. Accordingly, when the thickness of the emulsion is increased, it is possible to increase the thickness of a formed print product, and when the thickness of the emulsion is reduced or no emulsion is applied, it is possible to reduce the thickness of a formed print product. As a result, it is possible to set the thicknesses of the electricity supply portions <NUM> and <NUM> to be different from those of the heating wires etc..

Note that a method in which an inkjet printer is used may be employed instead of screen printing. In this method, the thickness of a print product is determined in accordance with the ink wetability of glass, and therefore, it is difficult to control the thickness of a print product. To address this, the concentration of conductive metal microparticles is adjusted by diluting the ink with a solvent, and thus it is possible to adjust the thickness of a fired product. As a result, it is possible to reduce the thicknesses of the heating wires etc. On the other hand, if the thicknesses of the heating wires etc. are increased, it is sufficient that printing is repeated, or less-diluted ink is used.

Here, the following tests were carried out in order to examine the thicknesses and the like of the electricity supply portions <NUM> and <NUM>.

As shown below, a glass plate made of soda-lime based glass with a thickness of <NUM> or a product obtained by layering a mask layer (having a composition as listed in Table <NUM> above) with a thickness of <NUM> on this glass plate was prepared, and a tensile test was carried out. The tensile test was as follows. An electricity supply portion with a length of <NUM> and a width of <NUM> was formed on the glass plate using a paste containing silver (conductive metal microparticles) or a paste containing copper (conductive metal microparticles), and lead-free solder was applied to a <NUM>-mm<NUM> area on the electricity supply portion. A wire was fixed to this lead-free solder, and this wire was pulled with a force of <NUM> N at a right angle with the glass plate. Then, the results were evaluated based on the following criteria.

It was found from the results above that the thickness of the electricity supply portion was preferably <NUM> or more. Note that, when silver and copper are compared, the linear thermal expansion coefficient of silver is <NUM>/(m·K), while the thermal expansion coefficient of copper is <NUM>/(m·K). Accordingly, since the thermal expansion coefficient of silver is higher, a difference in thermal expansion coefficient between silver and the glass plate is greater. Therefore, when the electricity supply portion is formed using silver, cracks are more likely to be generated. Accordingly, the electricity supply portion was formed using silver in Test <NUM>, which will be described next. In particular, a silver paste containing metal in an amount of <NUM>% after firing was used. Note that a difference in thermal expansion coefficient between the mask layer and the glass plate is smaller than that between silver and the glass plate, and therefore, an influence of the mask layer is considered as being negligible.

Three types of glass plates having different thicknesses were used, and electricity supply portions made of silver with different thicknesses were formed. A wire was connected to the electricity supply portion via lead-free solder in the same manner as in Test <NUM>. However, in Test <NUM>, a mask layer was not formed, and the electricity supply portion was formed directly on the glass plate. The thus-prepared samples were subjected to the above-described tensile test and a ring bending test (ASTM-C1499-<NUM>).

In the ring bending test, as shown in <FIG>, a load ring with a diameter of <NUM> was disposed on the electricity supply portion, and a support ring with a diameter of <NUM> was disposed on the lower surface of the glass plate. Then, the electricity supply portion was pressed using the load ring at a stress rate of <NUM> MPa/sec, and the fracture stress (fracture strength) of the glass plate was calculated. The results were as follows.

<FIG> is a graph showing relationships between the thickness of the electricity supply portion and fracture strength extracted from Table <NUM>. It was found from the graph shown in <FIG> that relationships between the thickness of the electricity supply portion and fracture strength were substantially the same irrespective of the type of glass. Accordingly, it was found that fracture strength did not vary depending on the type of glass. Moreover, the relationship between the thickness of the electricity supply portion (x below) and fracture strength (y below) is expressed by Formula (<NUM>) below based on the graph shown in <FIG>.

<FIG> is a graph showing relationships between the reciprocal of the square of the thickness of the glass plate and fracture strength extracted from Table <NUM>, and further shows the results of the tensile test. As shown in <FIG>, a relational expression y=<NUM>. 8x, where x is the reciprocal of the square of the thickness Dx of the glass plate and y is fracture strength (H), was considered as a limit of whether or not the electricity supply portion peeled away in the tensile test. That is, it was found that, when Formula (<NUM>) above is satisfied, it is possible to suppress peeling of the electricity supply portion from the glass plate.

Moreover, Formula (<NUM>) above can be derived from Formula (<NUM>) and Formula (<NUM>). That is, the relationship between the thickness of the electricity supply portion and the glass plate can be defined. <FIG> illustrates Formula (<NUM>). Note that, in the above-mentioned examples, a silver paste that contains metal microparticles in an amount of <NUM>% after firing was used, but the relationships of the above-mentioned formulae are satisfied even when a silver paste contains metal microparticles in an amount of <NUM>% or less after firing. This is true. The reason for this is that, when the content of metal microparticles is reduced, the amount of metal that controls the thermal expansion coefficient is reduced, and thus the thermal expansion coefficient tends to decrease. The same applies to cases where metal microparticles other than silver microparticles are used. The reason for this is that, for example, the thermal expansion coefficient of silver is higher than that of copper.

<NUM>-<NUM>
The wiring pattern of the heating body <NUM> is not limited to that shown in the embodiment above, and various patterns can be employed. For example, the number of the main portions <NUM> and <NUM> of the first and second heating wires <NUM> and <NUM>, the number of the coupling portions <NUM> and <NUM>, the orientations of the main portions <NUM> and <NUM>, the lengths of the connection wires <NUM>, the orientations of the connection wires <NUM>, the positions of the electricity supply portions <NUM> and <NUM>, and the like can be changed as appropriate. Moreover, although the two heating wires <NUM> and <NUM> are connected in parallel in the embodiment above, three or more heating wires may also be connected in parallel. Alternatively, a single heating wire may also be connected to the electricity supply portions <NUM> and <NUM> in series. Furthermore, the heating wires <NUM> and <NUM> and the connection wires <NUM> may have the same wire width. For example, the sizes of the coupling portions <NUM> and <NUM> of the heating wires <NUM> and <NUM>, and the connection wires <NUM> can also be made larger than the main portions <NUM> and <NUM>. This makes it possible to reduce an amount of heat generated by portions that do not contribute to heating of the imaging window <NUM>.

Moreover, the shape of the imaging window <NUM> need not be a trapezoidal shape, and can be changed as appropriate as long as images can be taken by the imaging device <NUM>. If the shape of the imaging window is changed, the wiring pattern of the heating body <NUM> can be changed as appropriate.

<NUM>-<NUM>
Although portions of the heating body <NUM> (the electricity supply portions <NUM> and <NUM>, connection wires <NUM>, and the coupling portions <NUM> and <NUM>) are disposed on the mask layer <NUM> in the embodiment above, they can also be disposed directly on the inner glass plate <NUM>.

Claim 1:
A glass plate module to which a wire (<NUM>) for supplying electric power is capable of being joined, comprising:
a glass plate (<NUM>);
a heating wire (<NUM>, <NUM>, <NUM>) disposed on the glass plate (<NUM>); and
an electricity supply portion (<NUM>, <NUM>) disposed on the glass plate (<NUM>), the wire (<NUM>) being connected to the electricity supply portion (<NUM>, <NUM>), and the electricity supply portion (<NUM>, <NUM>) supplying electric power to the heating wire (<NUM>, <NUM>, <NUM>),
wherein the heating wire (<NUM>, <NUM>, <NUM>) is formed using a conductive print that contains, as a main component, the same metal microparticles as those contained in the electricity supply portion (<NUM>, <NUM>),
the electricity supply portion (<NUM>, <NUM>) is formed using conductive print that contains, as a main component, metal microparticles whose thermal expansion coefficient is larger than that of the glass plate (<NUM>), and
the electricity supply portion (<NUM>, <NUM>) is thinner than the heating wire (<NUM>, <NUM>, <NUM>).