Vehicular window glass

Abstract

This vehicular window glass includes a glass plate for a window of a vehicle and a defogger provided on the glass plate. The defogger includes: a pair of first bus bars extending in the vertical direction of the glass plate; one or a plurality of first heating wires connected between the pair of first bus bars and extending in the lateral direction of the glass plate; a pair of second bus bars extending in the vertical direction of the glass plate; and a plurality of second heating wires connected between the pair of second bus bars, above or below the one or the plurality of first heating wires, and extending in the lateral direction of the glass plate. A resistance value per unit length of the first bus bar is equal to or less than a resistance value per unit length of the second bus bar.

Description

Vehicle window glass

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to vehicle glazings.

[0002] BACKGROUND ART A conventional technology for a vehicle rear glass that is disposed inside the vehicle and has an antenna and a defogger heating wire formed thereon, which combines the defrosting of an imaging range (wiring prohibited area) of an on-board camera that images the outside of the vehicle through the rear glass and the securing of an area for arranging an antenna, includes a vehicle window glass that includes a glass plate for a vehicle window, a defogger provided on the glass plate, and an antenna provided on the glass plate, wherein the defogger has a first defrosting area formed by a pair of bus bars extending in the vertical direction of the glass plate and a plurality of first heating wires connected between the pair of bus bars and extending in the left-right direction of the glass plate, and a second defrosting area formed to surround the wiring prohibited area by at least one second heating wire connected to the pair of bus bars or the first defrosting area and extending to one side in the vertical direction, and the antenna is provided in at least one area to the left of the second defrosting area or to the right of the second defrosting area. The pair of bus bars includes a bus bar (partial bus bar) connected to the plurality of first heating wires and a bus bar (partial bus bar) connected to the at least one second heating wire (see, for example, Patent Document 1).

[0003] International Publication No. 2019 / 017246

[0004] In the conventional vehicle window glass, the resistance per unit length of the bus bars (partial bus bars) connected to the plurality of first heating wires and the bus bars (partial bus bars) connected to the at least one second heating wire is not particularly adjusted. In such a case, for example, if the resistance per unit length of the bus bar connected to the at least one second heating wire is low, the at least one second heating wire will become thick, which may obstruct visibility.

[0005] Therefore, one aspect of the present disclosure provides a vehicle window glass that provides good visibility.

[0006] A vehicle window glass according to an embodiment of the present disclosure includes a glass plate for a vehicle window and a defogger provided on the glass plate, wherein the defogger has: a pair of first bus bars extending in a vertical direction of the glass plate; one or more first heating wires connected between the pair of first bus bars and extending in a left-right direction of the glass plate; a pair of second bus bars extending in the vertical direction of the glass plate; and a plurality of second heating wires connected between the pair of second bus bars above or below the one or more first heating wires and extending in the left-right direction of the glass plate, wherein a resistance value per unit length of the first bus bar is equal to or less than a resistance value per unit length of the second bus bar.

[0007] According to the present disclosure, a vehicle window glass with good visibility can be provided.

[0008] Fig. 1 is a plan view showing an example of the configuration of a vehicle window glass of an embodiment as viewed from inside the vehicle. Fig. 2 is a diagram showing an enlarged view of an example of the configuration of a portion around a wiring prohibited area in the overall configuration of the vehicle window glass of an embodiment. Fig. 3 is a diagram showing an example of an equivalent circuit of a pair of first bus bars and a first heating ray between a pair of power supply parts of the vehicle window glass of an embodiment. Fig. 4 is a diagram showing an example of a calculation result of the width of the first heating ray of a comparative vehicle window glass. Fig. 5 is a diagram showing an example of a calculation result of the width of the first heating ray of the vehicle window glass of an embodiment. Fig. 6 is a plan view showing an example of the configuration of a vehicle window glass of a modified embodiment of an embodiment.

[0009] Embodiments Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. In each embodiment, deviations in directions such as parallel, right-angle, horizontal, vertical, up-down, and left-right are permitted to a degree that does not impair the effects of the present disclosure. Furthermore, a diagram showing a glass sheet for a vehicle window (hereinafter also referred to as "window glass") shows the glass surface of the window glass viewed from the opposite side, and shows the window glass installed in the vehicle from the perspective of an occupant looking from inside the vehicle (interior view). Furthermore, if the window glass is a windshield installed in the front of the vehicle or a rear glass installed in the rear of the vehicle, the up-down direction in the diagram showing the window glass corresponds to the up-down direction of the vehicle, and the left-right direction corresponds to the width direction of the vehicle. Furthermore, the window glass is not limited to a windshield or a rear glass, and may be, for example, a side glass installed on the side of the vehicle. In addition, in the drawings showing window glass, the direction parallel to the X-axis (X-axis direction), the direction parallel to the Y-axis (Y-axis direction), and the direction parallel to the Z-axis (Z-axis direction) represent the left-right direction of the glass plate, the up-down direction of the glass plate, and the direction perpendicular to the surface of the glass plate, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are mutually orthogonal. Furthermore, a plan view refers to a view from an XY plane.

[0010] 1 is a plan view showing an example of the configuration of a vehicle window glass 100 as viewed from inside the vehicle. As an example, the vehicle window glass 100 has an axisymmetric configuration with a straight line (center line C) passing through the center in the left-right direction in the up-down direction as an axis of symmetry in a plan view.

[0011] The vehicle window glass 100 shown in Fig. 1 is an example of a rear window attached to the rear of a vehicle. The vehicle window glass 100 includes a glass plate 110 for a vehicle window and a defogger 120 provided on the glass plate 110. The defogger 120 has a pair of first bus bars 130LA, 130RA, a pair of second bus bars 130LB, 130RB, and a plurality of heating wires 140.

[0012] The first bus bars 130LA, 130RA, the second bus bars 130LB, 130RB, and the multiple heating wires 140 are formed, for example, by printing and baking a paste containing a conductive metal (e.g., silver paste) on the interior surface of the glass plate 110. Examples of methods that can be used to print the paste containing the conductive metal include screen printing, offset printing, gravure printing, flexographic printing, and inkjet printing. The first bus bars 130LA, 130RA, the second bus bars 130LB, 130RB, and the multiple heating wires 140 are formed from the same conductive material. The first bus bars 130LA, 130RA, the second bus bars 130LB, 130RB, and the multiple heating wires 140 formed in this manner have substantially the same thickness. In the following description, it is assumed that the thicknesses of the first bus bars 130LA, 130RA, the second bus bars 130LB, 130RB, and the plurality of heating wires 140 are the same.

[0013] Since the thickness of the first bus bars 130LA, 130RA and the second bus bars 130LB, 130RB is the same, the thicker (wider) the width of the first bus bars 130LA, 130RA and the second bus bars 130LB, 130RB, the lower the resistance value per unit length.

[0014] The thickness of the pair of first bus bars 130LA, 130RA, the pair of second bus bars 130LB, 130RB, and the plurality of heating wires 140 may be 5 μm or more and 20 μm or less. The width (line width) of the plurality of heating wires 140 may be 0.15 mm or more and 1.0 mm or less, or 0.15 mm or more and 0.5 mm or less. Hereinafter, the width of the plurality of heating wires 140 refers to the line width.

[0015] The method for forming the pair of first bus bars 130LA, 130RA, the pair of second bus bars 130LB, 130RB, and the plurality of heating wires 140 is not limited to the above-described method. For example, the pair of first bus bars 130LA, 130RA, the pair of second bus bars 130LB, 130RB, and the plurality of heating wires 140 may be formed by providing a linear or foil body containing a conductive material such as copper on the interior or exterior surface of the glass plate 110. Alternatively, the pair of first bus bars 130LA, 130RA, the pair of second bus bars 130LB, 130RB, and the plurality of heating wires 140 may be attached to the glass plate 110 with an adhesive or the like, or may be provided inside (inner layer of) the glass plate 110 itself.

[0016] Furthermore, the thicknesses of the first bus bars 130LA, 130RA, the second bus bars 130LB, 130RB, or the plurality of heating wires 140 may be different. When the thicknesses of the first bus bars 130LA, 130RA and the second bus bars 130LB, 130RB are different, the resistance value per unit length may be set taking the thickness into consideration.

[0017] A camera 20 for capturing an image of the outside of the vehicle can be mounted on the interior side of the vehicle window glass 100. Fig. 1 is a plan view showing the vehicle window glass 100 as seen from the interior side of the vehicle, with the position of the camera 20 indicated by a dashed line. The position of the camera 20 is specifically the position of the lens of the camera 20. The imaging range of the camera 20 is set to a wiring prohibited area 113 in a plan view.

[0018] The camera 20 is mounted on the interior side of the vehicle relative to the glass plate 110, and is a device (image capturing unit) that captures an image of the outside of the vehicle (the rear of the vehicle in this embodiment) through the glass plate 110. For example, an image captured by the camera 20 is displayed on a display inside the vehicle, thereby helping the driver of the vehicle to visually recognize the situation around the vehicle.

[0019] A lamp may be provided in the wiring prohibited area 113 instead of the camera 20. The lamp may be, for example, a high-mounted stop lamp. The lamp emits light to notify the driver of a following vehicle that the brakes of the vehicle have been applied. The lamp is mounted on the interior side of the glass plate 110 and emits light through the glass plate 110 toward the outside of the vehicle (toward the rear of the vehicle in this embodiment).

[0020] <Glass Plate 110> The glass plate 110 is an example of a glass plate for a vehicle window. The glass plate 110 may be either a single-plate glass or a laminated glass. Below, an embodiment in which the glass plate 110 is a single-plate glass will be described.

[0021] The outer shape of the glass plate 110 is approximately rectangular. The upper edge 110U represents the glass edge on the upper side of the glass plate 110, and the lower edge 110B represents the glass edge on the lower side of the glass plate 110 (opposite the upper edge 110U side). The left edge 110L represents the glass edge on the left side of the glass plate 110, and the right edge 110R represents the glass edge on the right side of the glass plate 110 (opposite the left edge 110L side). The left edge 110L is the glass edge adjacent to the left side of the upper edge 110U and the lower edge 110B, and the right edge 110R is the glass edge adjacent to the right side of the upper edge 110U and the lower edge 110B.

[0022] The glass plate 110 has a pair of side edges. The left edge 110L is an example of a first side edge, which is one of the pair of side edges, and the right edge 110R is an example of a second side edge, which is the other of the pair of side edges. The connection between the upper edge 110U and the left edge 110L is connected with a curvature, but may be connected without a curvature. The shapes of the connection between the other edges are similar.

[0023] The glass plate 110 has a first antifogging area 111, a second antifogging area 112, a wiring prohibited area 113, a hole 114, and a shielding layer 115. As an example, the center of the left-right width of the wiring prohibited area 113 is located on the center line C, and the center of the hole 114 is also located on the center line C. The hole 114 is a through-hole through which a wiper pivot (the rotation axis of the wiper) passes. The wiping area 114A is a fan-shaped area of ​​the entire glass plate 110 that can be wiped by the wiper.

[0024] The following description will be made with reference to Fig. 2 in addition to Fig. 1. Fig. 2 is an enlarged view showing an example of the configuration of a portion around the wiring prohibited area 113 in the overall configuration of the vehicle window glass 100.

[0025] <First antifogging region 111> The first antifogging region 111 is the antifogging region of the glass plate 110 excluding the second antifogging region 112 located in the upper center and the wiring prohibited region 113 surrounded by the second antifogging region 112. The antifogging region of the glass plate 110 is a region that extends inward from the substantially rectangular region of the entire glass plate 110 in which the multiple heating wires 140 are provided, and is an antifogging region in which fogging is removed by the heat generated by the multiple heating wires 140.

[0026] The first antifogging region 111 is a generally U-shaped region consisting of a portion of the antifogging region of the glass plate 110 from the lower edge 110B side to the lower end of the second antifogging region 112, and left and right portions of the second antifogging region 112. The portion of the antifogging region from the lower edge 110B side to the lower end of the second antifogging region 112 is, for example, a portion where ten second heating wires 140A, the third to twelfth from the top, of the twelve heating wires 140, extend in the left-right direction. The outer edge of the first antifogging region 111 is located outside the opening 115A of the shielding layer 115 on the lower edge 110B side, is located outside the opening 115A of the shielding layer 115 on the left edge 110L side and the right edge 110R side except for the upper end side of the glass plate 110, and is located inside the opening 115A of the shielding layer 115 near the edge of the opening 115A on the upper edge 110U side. Note that the first and second heating wires 140 from the top may extend further upward on the left and right sides of the second antifogging region 112, so that the entire outer edge of the first antifogging region 111 is located outside the opening 115A of the shielding layer 115.

[0027] <Second antifogging region 112> The second antifogging region 112 is the central portion of the upper end of the antifogging region of the glass plate 110 in the horizontal direction, excluding the wiring prohibited region 113. The upper end portion of the antifogging region is, for example, the portion in the vertical direction of the glass plate 110 where the first heating wires 141 and 142, which are the first and second heating wires from the top of the twelve heating wires 140, are provided. The second antifogging region 112 overlaps with the curved portions 141A and 142A of the first heating wires 141 and 142. Hereinafter, when describing the position of each of the twelve heating wires 140 counting from the top, the term "number" may be used simply.

[0028] The second antifogging region 112 is a substantially rectangular annular region surrounding the wiring prohibited region 113. An inner edge 112A of the second antifogging region 112 is the inner edge of the substantially rectangular annular second antifogging region 112. The region inside the inner edge 112A is not included in the second antifogging region 112. The wiring prohibited region 113 is located inside the inner edge 112A of the second antifogging region 112. As an example, the lower end of the second antifogging region is located between the second first heating wire 142 and the third second heating wire 140A.

[0029] <Wiring Prohibited Area 113> The wiring prohibited area 113 is an area surrounded by the second anti-fogging area 112 in the central portion in the left-right direction on the upper edge 110U side of the glass plate 110. The wiring prohibited area 113 is an area where wiring of heating wires, antennas, etc. is prohibited, and is, for example, a trapezoidal area in a plan view with a bottom base longer than an top base. The outer edge of the wiring prohibited area 113 is trapezoidal. The wiring prohibited area 113 includes an imageable area defined by the angle of view of the camera 20 installed inside the vehicle facing the rear, and is an area wider than the imageable area defined by the angle of view. Images captured by the camera 20 can be displayed on a display or the like of the vehicle.

[0030] The curved portion 141A of the first heating wire 141 surrounds the wiring prohibited area 113 on three sides, the upper side, right side, and lower side, and is located outside the wiring prohibited area 113, thereby preventing the curved portion 141A from appearing in the image captured by the camera 20. Furthermore, when a voltage is applied between the pair of first bus bars 130LA, 130RA, the first heating wire 141 is energized and generates heat, and the heat is transferred from the second anti-fogging area 112 outside the wiring prohibited area 113 to the wiring prohibited area 113, thereby removing fogging within the wiring prohibited area 113.

[0031] Here, as an example, a configuration will be described in which the wiring prohibited area 113 is located at the center in the left-right direction on the upper edge 110U side of the glass plate 110, but the wiring prohibited area 113 may be located in a part other than the center in the left-right direction on the upper edge 110U side of the glass plate 110. As an example, the wiring prohibited area 113 may be located to the right or left of the center in the left-right direction on the upper edge 110U side of the glass plate 110.

[0032] <Hole 114> The hole 114 is located at the center in the left-right direction on the lower edge 110B side of the glass plate 110, and is a through-hole that penetrates the glass plate 110 in the thickness direction (Z-axis direction). The hole 114 is a through-hole through which a wiper pivot (the rotation axis of the wiper) passes. The hole 114 is provided in a protrusion 115B that protrudes upward from the lower edge 110B side of the opening 115A of the shielding layer 115. The protrusion 115B has an opening that avoids the hole 114.

[0033] The motor that rotates the wiper pivot is fixed to a metal inner panel or reinforcement (metal reinforcing material) of the back door to which the vehicle window glass 100 serving as the rear glass is attached, and the wiper arm is fixed to the wiper pivot on the vehicle exterior side of the glass plate 110. The wiping region 114A is a fan-shaped area in which the wiper blade attached to the wiper arm can wipe the vehicle exterior surface of the glass plate 110.

[0034] The wiping region 114A overlaps the left-right center of the first anti-fogging region 111 and substantially the entire second anti-fogging region 112. Because the curved portions 141A and 142A of the first heating wires 141 and 142 are located inside the second anti-fogging region 112, the upper end of the wiping region 114A overlaps with the curved portions 141A and 142A of the first heating wires 141 and 142. Because the upper end of the fan-shaped wiping region 114A protrudes above the linear portions on the left and right sides of the first heating wires 141 and 142, the upwardly curved curved portions 141A and 142A are provided in the first heating wires 141 and 142, so that the entire wiping region 114A can be heated and defogging can be removed.

[0035] Furthermore, the wiping area 114A overlaps with the wiring prohibited area 113. The wiring prohibited area 113 is located at the top of the center in the left-right direction of the wiping area 114A. By arranging the wiring prohibited area 113 where the camera 20 is located inside the wiper wiping area 114A, a clear field of view can be ensured within the imaging range of the camera 20 when the wiper is operated during rainy or snowy weather, or when dust or other particles are attached to the exterior surface of the glass plate 110.

[0036] Here, an example will be described in which the hole 114 is located at the center in the left-right direction on the lower edge 110B side of the glass plate 110, but the hole 114 may be located at a position other than the center in the left-right direction on the lower edge 110B side of the glass plate 110. As an example, the hole 114 may be located to the right or left of the center in the left-right direction on the lower edge 110B side of the glass plate 110.

[0037] The hole 114 may be located at the center of the upper edge 110U of the glass plate 110 in the left-right direction, or to the right or left of the center. In this case, the wiping area 114A has a shape rotated 180 degrees in a plan view, and the heating wires 140 also have a shape rotated 180 degrees in a plan view. That is, the heating wires 140 are configured such that, from bottom to top, the first heating wire 141, the second first heating wire 142, and the third to twelfth second heating wires 140A are arranged, and the curved portions 141A and 142A of the first heating wires 141 and 142 are curved downward.

[0038] <Shielding Layer 115> The shielding layer 115 is a frame-shaped layer provided along the outer edges (upper edge 110U, left edge 110L, lower edge 110B, and right edge 110R) of the glass plate 110. The shielding layer 115 has an opening 115A that exposes substantially the entire area inside the outer edges of the glass plate 110, and a convex portion 115B that protrudes upward from the lower edge 110B side of the opening 115A. The convex portion 115B protrudes upward to surround the hole 114, and has an opening that avoids the hole 114. Note that the shielding layer 115 has a convex portion that protrudes downward from the upper edge 110U side of the opening 115A, and an opening provided in the convex portion, and the opening may surround the wiring prohibited area 113.

[0039] A specific example of the shielding layer 115 is ceramics such as a black ceramic layer. The shielding layer 115 is formed by printing and baking a ceramic paste containing a black pigment and glass frit on the interior surface of the glass plate 110. Methods that can be used to print the ceramic paste containing the black pigment and glass frit include screen printing, offset printing, gravure printing, flexographic printing, and inkjet printing. When the glass plate 110 is viewed from outside the vehicle, the portion overlapping with the shielding layer 115 is invisible from outside the vehicle, resulting in a glass plate 110 with an excellent design.

[0040] <Defogger 120> The defogger 120 is an electrically heated conductor pattern that removes fogging from the glass plate 110. The defogger 120 has a plurality of heating wires 140 extending in the left-right direction of the glass plate 110, first bus bars 130LA, 130RA and second bus bars 130LB, 130RB that supply power to the plurality of heating wires 140, and power supply portions 135L, 135R. The first bus bars 130LA, 130RA form a pair, and the second bus bars 130LB, 130RB form a pair.

[0041] In this embodiment, twelve heating wires 140 extending in the left-right direction of the glass plate 110 so as to run parallel to each other, and a pair of first bus bars 130LA, 130RA and a pair of second bus bars 130LB, 130RB connected to the twelve heating wires 140 are provided on the glass plate 110.

[0042] The first bus bar 130LA and the second bus bar 130LB are connected to a power supply unit 135L, and the first bus bar 130RA and the second bus bar 130RB are connected to a power supply unit 135R. When a voltage is applied from the power supply units 135L and 135R between the pair of first bus bars 130LA and 130RA and the pair of second bus bars 130LB and 130RB, the twelve heating wires 140 are energized and generate heat, thereby removing fogging from the glass sheet 110.

[0043] <Pair of First Bus Bars 130LA, 130RA> The pair of first bus bars 130LA, 130RA are conductor patterns that extend in the up-down direction along the left edge 110L and the right edge 110R of the glass plate 110. First and second first heating wires 141 and 142 are connected between the pair of first bus bars 130LA, 130RA. The pair of first bus bars 130LA, 130RA are located outside the opening 115A of the shielding layer 115 and overlap with the shielding layer 115.

[0044] First bus bar 130LA has an upper end 131LA and a lower end 132LA, and extends between upper end 131LA and lower end 132LA in the vertical direction. First bus bar 130RA has an upper end 131RA and a lower end 132RA, and extends between upper end 131RA and lower end 132RA in the vertical direction. Upper ends 131LA and 131RA are examples of first ends, and lower ends 132LA and 132RA are examples of second ends.

[0045] For example, first bus bars 130LA and 130RA have a shape that is line-symmetrical with respect to center line C. Lower ends 132LA and 132RA of first bus bars 130LA and 130RA are connected to power feeders 135L and 135R, respectively. DC power is supplied to first bus bars 130LA and 130RA from a DC power source (not shown) of the vehicle via power feeders 135L and 135R.

[0046] Furthermore, by connecting lower ends 132LA and 132RA of first bus bars 130LA and 130RA to power feeders 135L and 135R, respectively, first bus bars 130LA and 130RA are fed with power directly from power feeders 135L and 135R without passing through second bus bars 130LB and 130RB. This allows the resistance value of first bus bars 130LA and 130RA to be reduced, and the width of one or more first heating wires 141 and 142 to be made thinner.

[0047] The first bus bars 130LA and 130RA are connected at their lower ends 132LA and 132RA to the second bus bars 130LB and 130RB, respectively. The upper ends 131LA and 131RA of the first bus bars 130LA and 130RA are located higher than the upper ends 131LB and 131RB of the second bus bars 130LB and 130RB, and the first and second first heating wires 141 and 142 are connected between the upper ends 131LA and 131RA. Of the 12 heating wires 140, only the first and second first heating wires 141 and 142 from the top are connected between the first bus bars 130LA and 130RA.

[0048] The width (width in the left-right direction) of the first bus bars 130LA and 130RA is greater than the width (width in the left-right direction) of the second bus bars 130LB and 130RB. Because the thickness of the first bus bars 130LA and 130RA and the thickness of the second bus bars 130LB and 130RB are equal, the resistance value per unit length of the first bus bars 130LA and 130RA is lower than the resistance value per unit length of the second bus bars 130LB and 130RB.

[0049] Even if the first heating wires 141, 142 provided on the upper side are longer than the third and subsequent second heating wires 140A, the resistance per unit length of the first bus bars 130LA, 130RA is lower than the resistance per unit length of the second bus bars 130LB, 130RB, so the width of the first heating wires 141, 142 can be narrowed. Therefore, even if one or more first heating wires 141, 142 longer than the second heating wire 140A are located on the upper side of the glass plate 110, good visibility can be obtained. The ability to narrow the width of the first heating wires 141, 142 will be described in detail later.

[0050] <Pair of Second Bus Bars 130LB, 130RB> The pair of second bus bars 130LB, 130RB are conductor patterns that extend in the up-down direction along the left edge 110L and the right edge 110R of the glass plate 110. Ten second heating wires 140A, from the third to the twelfth, are connected between the pair of second bus bars 130LB, 130RB. The pair of second bus bars 130LB, 130RB are located outside the opening 115A of the shielding layer 115 and overlap with the shielding layer 115.

[0051] The second bus bar 130LB has an upper end 131LB and a lower end 132LB and extends between the upper end 131LB and the lower end 132LB in the vertical direction. The second bus bar 130RB has an upper end 131RB and a lower end 132RB and extends between the upper end 131RB and the lower end 132RB in the vertical direction. The upper ends 131LB and 131RB are examples of third ends, and the lower ends 132LB and 132RB are examples of fourth ends.

[0052] For example, the second bus bars 130LB and 130RB have a shape that is symmetrical with respect to the center line C. The second bus bars 130LB and 130RB are connected to power feeding points 135L and 135R, respectively, between their lower ends 132LB and 132RB and their upper ends 131LB and 131RB. In other words, the second bus bars 130LB and 130RB are connected to the lower ends 132LA and 132RA of the first bus bars 130LA and 130RA between their lower ends 132LB and 132RB and their upper ends 131LB and 131RB. DC power is supplied to the second bus bars 130LB and 130RB from a DC power source (not shown) of the vehicle via the power feeding points 135L and 135R.

[0053] Upper ends 131LB and 131RB of the second bus bars 130LB and 130RB are located lower than upper ends 131LA and 131RA of the first bus bars 130LA and 130RA. Lower ends 132LB and 132RB of the second bus bars 130LB and 130RB are located lower than lower ends 132LA and 132RA of the first bus bars 130LA and 130RA. Ten second heating wires 140A, from the third to the twelfth, are connected to the second bus bars 130LB and 130RB between the upper ends 131LB and 131RB and the lower ends 132LB and 132RB.

[0054] The second bus bars 130LB and 130RB are connected to the power supply portions 135L and 135R between the lower ends 132LB and 132RB and the upper ends 131LB and 131RB, respectively, which facilitates equalization of the power density in the second heating wires 140A. As a result, a configuration is obtained in which it is easier to achieve equalization of the power density in all the heating wires 140.

[0055] Furthermore, lower ends 132LB and 132RB are positioned lower than lower ends 132LA and 132RA of first bus bars 130LA and 130RA, so that second bus bars 130LB and 130RB extend lower than power feeding portions 135L and 135R. This configuration makes it easier to achieve equalized power density among the ten second heating wires 140A.

[0056] The width (width in the left-right direction) of the second bus bars 130LB and 130RB is narrower than the width (width in the left-right direction) of the first bus bars 130LA and 130RA. Because the thickness of the second bus bars 130LB and 130RB is the same as that of the first bus bars 130LA and 130RA, the resistance value per unit length of the second bus bars 130LB and 130RB is higher than the resistance value per unit length of the first bus bars 130LA and 130RA.

[0057] <Power supply portions 135L, 135R> Power supply portions 135L, 135R are conductor patterns provided respectively along left edge 110L and right edge 110R of glass plate 110. Power supply portions 135L, 135R are provided at the connection portions between lower end portions 132LA, 132RA of first bus bars 130LA, 130RA and second bus bars 130LB, 130RB.

[0058] Lower ends 132LA and 132RA of first bus bars 130LA and 130RA are connected to portions between upper ends 131LB and 131RB and lower ends 132LB and 132RB of second bus bars 130LB and 130RB. Therefore, power supply portions 135L and 135R are connected to portions between upper ends 131LB and 131RB and lower ends 132LB and 132RB of second bus bars 130LB and 130RB.

[0059] Connectors or the like are connected to the power supply units 135L and 135R. The power supply units 135L and 135R are connected to, for example, a DC power supply (not shown) of the vehicle via connectors or the like. For example, the power supply unit 135L is connected to one terminal (for example, a positive terminal) of the DC power supply of the vehicle, and the power supply unit 135R is connected to the other terminal (for example, a negative terminal) of the DC power supply of the vehicle. DC power is supplied to the power supply units 135L and 135R from a DC power supply (not shown) of the vehicle. The DC power supplied from the DC power supply of the vehicle is supplied from the power supply units 135L and 135R to the twelve heating wires 140 via the first bus bars 130LA and 130RA and the second bus bars 130LB and 130RB.

[0060] Furthermore, the power supply units 135L, 135R are preferably provided within a range from the upper end of the glass plate 110 to two-thirds of the length of the glass plate 110 in the vertical direction. The power supply units 135L, 135R are connected to the lower ends 132LA, 132RA of the first bus bars 130LA, 130RA and the portions between the upper ends 131LB, 131RB and the lower ends 132LB, 132RB of the second bus bars 130LB, 130RB. If the power supply units 135L, 135R are provided on the lower end side of the glass plate 110, the first bus bars 130LA, 130RA will be longer, which will increase the voltage drop in the first bus bars 130LA, 130RA and make it difficult to equalize the power density of the ten second heating wires 140A connected to the second bus bars 130LB, 130RB. To avoid such a situation, it is preferable that the pair of power supply sections 135L, 135R are arranged within a range from the upper end of the glass plate 110 to 2 / 3 of the vertical length of the glass plate 110, and it is more preferable that they are arranged within a range from 1 / 3 to 2 / 3 of the vertical length of the glass plate 110.

[0061] Before explaining the details of the configuration of the heating wire 140, we will use the equivalent circuit of Figure 3 to explain why the resistance value per unit length of the first bus bars 130LA and 130RA is made lower than the resistance value per unit length of the second bus bars 130LB and 130RB.

[0062] FIG. 3 is a diagram showing an example of an equivalent circuit of first bus bars 130LA, 130RA and first heating wires 141 and 142 between power supply portions 135L, 135R.

[0063] The length of the first heating wires 141 and 142 connected between the first bus bars 130LA and 130RA is longer than the length of the third and subsequent second heating wires 140A. As will be described in detail later, this is because the first heating wires 141 and 142 have curved portions 141A and 142A that curve upward in correspondence with the wiping area 114A.

[0064] The length of the first heating wires 141 and 142 may lead to an increase in electrical resistance. Furthermore, if the electrical resistance of the first heating wires 141 and 142 increases, the balance of power density with the third and subsequent second heating wires 140A may be disrupted, and the electrical heat distribution throughout the entire heating wire 140 may deteriorate. In such a case, if the width of the first heating wires 141 and 142 is increased to reduce the electrical resistance in order to improve the electrical heat distribution, this may obstruct the view at the upper end of the glass plate 110.

[0065] Each of the twelve heating wires 140 is required to have a width that is narrow to a certain extent so as not to obstruct the field of view. For example, the width of each heating wire 140 is preferably 1 mm or less, and 1 mm or less is one standard for the width of the heating wire 140.

[0066] In this embodiment, the power density is made uniform throughout the heating wires 140 to maintain a good level of electric heat distribution throughout the heating wires 140, while the widths of the first heating wires 141 and 142, which are longer than the second heating wire 140A, are narrowed by setting the resistance per unit length of the first bus bars 130LA and 130RA lower than the resistance per unit length of the second bus bars 130LB and 130RB. Note that the power density throughout the heating wires 140 refers to the power load (W) per unit area (m2) of the first anti-fogging region 111 and the second anti-fogging region 112 for the 12 heating wires 140 provided in the first anti-fogging region 111 and the second anti-fogging region 112 of the glass sheet 110, and is expressed in W / m2.

[0067] In the equivalent circuit of FIG. 3, the voltage between power feeding unit 135L and power feeding unit 135R corresponds to the voltage of the DC power supply of the vehicle, and is therefore considered to be constant.

[0068] Under the condition that the voltage between power supply unit 135L and power supply unit 135R is constant, the power density in first heating wires 141 and 142 can be increased without thickening first heating wires 141 and 142 by increasing the voltage drop in first heating wires 141 and 142. To achieve this, the voltage drop in first bus bars 130LA and 130RA can be reduced, in other words, the resistance value of first bus bars 130LA and 130RA can be reduced.

[0069] From this perspective, the first bus bars 130LA and 130RA are made thicker in the vehicle window glass 100. The widths of the first bus bars 130LA and 130RA are made equal to or greater than the widths of the second bus bars 130LB and 130RB in the vehicle window glass 100. When the thicknesses are equal, the relationship in which the resistance value per unit length of the first bus bars 130LA and 130RA is equal to or less than the resistance value per unit length of the second bus bars 130LB and 130RB can be achieved by the width alone, which simplifies manufacturing and management of the resistance values.

[0070] The width of the first bus bars 130LA and 130RA is preferably wider than the width of the second bus bars 130LB and 130RB. This allows the width of the first heating wires 141 and 142 to be narrower, resulting in better visibility. This also makes it easier to reduce the resistance of the first bus bars 130LA and 130RA, and to equalize the power density among the ten second heating wires 140A while keeping the width of the first heating wires 141 and 142 at 1 mm or less.

[0071] Here, as an example, the thicknesses of the first bus bars 130LA and 130RA and the second bus bars 130LB and 130RB are equal to each other. Therefore, when the widths of the first bus bars 130LA and 130RA are equal to or greater than the widths of the second bus bars 130LB and 130RB, the resistance per unit length of the first bus bars 130LA and 130RA is equal to or less than the resistance per unit length of the second bus bars 130LB and 130RB.

[0072] Furthermore, the width of the first bus bars 130LA and 130RA being greater than the width of the second bus bars 130LB and 130RB corresponds to the resistance value per unit length of the first bus bars 130LA and 130RA being lower than the resistance value per unit length of the second bus bars 130LB and 130RB. It is preferable that the width of the first bus bars 130LA and 130RA be made greater within the allowable range in terms of the layout of the glass plate 110.

[0073] <Hot wires 140> The twelve hot wires 140 are conductor patterns connected between the first bus bars 130LA, 130RA and the second bus bars 130LB, 130RB. Here, as an example, it is assumed that current flows from the first bus bar 130LA and the second bus bar 130LB on the left to the first bus bar 130RA and the second bus bar 130RB on the right. Furthermore, the width of the hot wires 140 refers to the line width.

[0074] Each of the twelve heating wires 140 has a left end connected to the left first bus bar 130LA or the left second bus bar 130LB, and a right end connected to the right first bus bar 130RA or the right second bus bar 130RB. The left end of each heating wire 140 is the connection between the left first bus bar 130LA or the left second bus bar 130LB and the heating wire 140, and the right end of each heating wire 140 is the connection between the right first bus bar 130RA or the right second bus bar 130RB and the heating wire 140. The left and right ends of the twelve heating wires 140 overlap the shielding layer 115.

[0075] The upper two of the twelve heat wires 140 are the first heat wires 141 and 142. The first heat wire 141 is the first heat wire located at the top, and the first heat wire 142 is the second heat wire from the top. Furthermore, the third to twelfth heat wires 140 from the top, other than the upper two heat wires 140 (first heat wires 141 and 142), are the second heat wires 140A. When the twelve heat wires 140 are not particularly distinguished from one another, they are simply referred to as heat wires 140.

[0076] Here, as an example, the first heating wire 141 has an asymmetric shape with a center line C passing through the center in the left-right direction of the glass plate 110 in the up-down direction as the axis of symmetry. The first heating wire 142 and the ten second heating wires 140A also have symmetric shapes with the center line C passing through the center in the left-right direction of the glass plate 110 in the up-down direction as the axis of symmetry. However, the first heating wire 142 and the ten second heating wires 140A do not have to have symmetric shapes with respect to the above-mentioned axis of symmetry.

[0077] <Third to Twelfth Second Heat Wires 140A> The third to twelfth second heat wires 140A are connected between the second bus bars 130LB and 130RB in a region of the first antifogging region 111 below the second antifogging region 112, and extend in the left-right direction. The third to eleventh second heat wires 140A do not overlap the shielding layer 115 except for the left and right ends, and are located inside the opening 115A. Furthermore, for the twelfth second heat wire 140A, a portion of the left and right sides of the protrusion 115B does not overlap with the shielding layer 115 and is located inside the opening 115A, but most of the protrusion 115B except for the left and right parts overlap with the shielding layer 115.

[0078] To heat the glass plate 110 evenly, the vertical spacing between the third to twelfth second heating wires 140A is approximately constant. Furthermore, the third to tenth second heating wires 140A preferably have approximately equal lengths between the second bus bars 130LB and 130RB and the same resistance. This allows for a uniform defrosting rate and prevents uneven defrosting. The eleventh and twelfth second heating wires 140A are longer than the third to tenth second heating wires 140A, but their resistances are preferably adjusted to provide equivalent power densities. This allows for a uniform defrosting rate between the third to tenth second heating wires 140A and the eleventh and twelfth second heating wires 140A, preventing uneven defrosting.

[0079] In order to avoid the protrusion 115B, the distance between the eleventh second heating wire 140A and the twelfth second heating wire 140A is narrower in the center in the left-right direction than in the left and right portions of the protrusion 115B. In this center portion, for example, the width of the portion of the twelfth second heating wire 140A that overlaps with the protrusion 115B may be widened to obtain a uniform temperature distribution. This is because the portion of the twelfth second heating wire 140A that overlaps with the protrusion 115B cannot be seen from the outside of the glass plate 110, so widening the width does not obstruct visibility.

[0080] The eleventh and twelfth second heating wires 140A are longer than the third to tenth second heating wires 140A. However, since they are located at the lower end of the glass plate 110 and partially overlap with the shielding layer 115, they are unlikely to obstruct visibility, and therefore can be made thicker as needed.

[0081] <First and Second First Heat Wires 141 and 142> The first heat wires 141 and 142, except for the left and right ends connected to the first bus bars 130LA and 130RA, are located inside the opening edge of the opening 115A of the shielding layer 115. Therefore, the first heat wires 141 and 142, except for the left and right ends, can be within the field of view of an occupant of a vehicle in which the vehicle window glass 100 is installed.

[0082] As described above, the first heating wires 141 and 142 have a wire width of 1 mm or less by making the resistance per unit length of the first bus bars 130LA and 130RA lower than the resistance per unit length of the second bus bars 130LB and 130RB. Furthermore, these first heating wires 141 and 142 achieve uniform power density in all heating wires 140, including the ten second heating wires 140A.

[0083] The first heating wires 141 and 142 have curved portions 141A and 142A, respectively, in their left-right central portions, which are curved upward to correspond to the wiping area 114A of the wiper. On the left and right sides of the curved portions 141A and 142A, the first heating wires 141 and 142 extend linearly in the left-right direction, similar to the third to twelfth second heating wires 140A, and are arranged at intervals approximately equal to the vertical intervals of the third to twelfth second heating wires 140A.

[0084] Here, a configuration will be described in which the first and second heating wires from the top among the twelve heating wires 140 are the first heating wires 141 and 142, but the heating wire 140 as the first heating wire may be only the first heating wire 141, or three or more heating wires 140 as the first heating wires may be provided. Also, here, a configuration will be described in which the line width of the first heating wires 141 and 142 is 1 mm or less, but this is not limited to 1 mm or less, and it is sufficient that a predetermined thin line width is realized to ensure good visibility in accordance with standards for the vehicle window glass 100, etc.

[0085] <Curved portion 141A of first heating wire 141> The curved portion 141A of the first heating wire 141 is located at the center in the left-right direction of the first heating wire 141, and as shown in FIG. 1 for example, it occupies approximately 3 / 5 of the left-right length of the first heating wire 141. As shown in FIG. 2, the curved portion 141A has bent portions 141A1 to 141A10. The curved portion 141A is located inside the wiping area 114A and the second defogging area 112. In FIG. 2, the linearly extending portions of the first heating wire 141 on the left and right sides are omitted in order to illustrate only the area surrounding the wiring prohibited area 113 of the overall configuration of the vehicle window glass 100.

[0086] Here, the configuration of the curved portion 141A of the first heating wire 141 will be described from left to right. In addition, the description may be made using a section between any two of the curved portions 141A1 to 141A10 of the curved portion 141A. For example, the section between the curved portion 141A1 and the curved portion 141A2 will be referred to as section 141A1-141A2.

[0087] <Sections 141A1-141A2> The first heating wire 141 starts from a linear portion on the left side, bends diagonally upward to the right at bend 141A1, and extends in an upwardly convex arc to bend 141A2. The first heating wire 141 extends in an upwardly convex arc from bend 141A1 to bend 141A2 along the upper edge of the wiping area 114A. The sections 141A1-141A2 are located inside the wiping area 114A and the second antifogging area 112.

[0088] The sections 141A1-141A2 straddle the center line C, and the bent portion 141A2 is located to the right of the upper right vertex of the wiring prohibited area 113, and the portions of the sections 141A1-141A2 on the bent portion 141A2 side extend above the upper base of the trapezoidal shape of the wiring prohibited area 113. The sections 141A1-141A2 extend above the wiring prohibited area 113 and are located outside the wiring prohibited area 113. This is to prevent the curved portion 141A from appearing in the image captured by the camera 20. Furthermore, because the apexes of the arc-shaped sections 141A1-141A2 are located on the center line C, the bent portion 141A2 is located to the right (+X-axis direction) of the apexes of the arc-shaped sections 141A1-141A2.

[0089] <Sections 141A2-141A3> The curved portion 141A bends downward (in the -Y-axis direction) at bend 141A2 and extends in the vertical direction (in the Y-axis direction) to bend 141A3. The sections 141A2-141A3 are parallel to the vertical direction. The bend 141A3 is located to the right of the bottom right vertex of the wiring prohibited area 113. The sections 141A2-141A3 extend to the right of the wiring prohibited area 113 and are located outside the wiring prohibited area 113. This is to prevent the curved portion 141A from appearing in images captured by the camera 20. The sections 141A2-141A3 are located inside the wiping area 114A and the second antifogging area 112.

[0090] <Sections 141A3-141A4> The curved portion 141A bends leftward (in the negative X-axis direction) at bend 141A3 and extends upward in a convex arc to bend 141A4. Sections 141A3-141A4 extend concentrically with the portions of sections 141A1-141A2 near center line C. "Concentric" here includes cases where the deviation of the centers of the circles is within 10 mm. The vertical distance between sections 141A3-141A4 and the portions of sections 141A1-141A2 that are at the same horizontal positions as sections 141A3-141A4 is constant. Bend 141A4 is located to the left of the bottom left vertex of the wiring prohibited area 113. As an example, the horizontal length of sections 141A3-141A4 is approximately twice the horizontal length of wiring prohibited area 113. Sections 141A3-141A4 extend below wiring prohibited area 113 and are located outside wiring prohibited area 113. This is to prevent curved portion 141A from appearing in images captured by camera 20. Sections 141A3-141A4 are located inside wiping area 114A and second defogging area 112.

[0091] <Sections 141A4-141A5> The curved portion 141A bends downward (in the -Y-axis direction) at bend 141A4 and extends up and down (in the Y-axis direction) to bend 141A5. The sections 141A4-141A5 are parallel to the up and down direction. For example, the up and down lengths of sections 141A4-141A5 are equal to the up and down lengths of sections 141A2-141A3. The sections 141A4-141A5 are located inside the wiping region 114A and the second antifogging region 112.

[0092] <Sections 141A5-141A6> Curved portion 141A bends diagonally upward to the right at bend 141A5 and extends in an upwardly convex arc shape to bend 141A6. Sections 141A5-141A6 extend in an arc shape concentric with the portions of sections 141A1-141A2 near center line C and sections 141A3-141A4. The vertical distance between sections 141A5-141A6 and sections 141A3-141A4 is constant and equal to the vertical distance between sections 141A1-141A2 and sections 141A3-141A4.

[0093] The bent portion 141A6 is located to the right of the center line C, and the length of the arc-shaped section from the bent portion 141A6 to the center line C is equal to the length of the arc-shaped section from the bent portion 141A5 to the center line C. In other words, the sections 141A5 to 141A6 are symmetrical with respect to the center line C. The sections 141A5 to 141A6 are located inside the wiping region 114A and the second antifogging region 112.

[0094] <Sections 141A6-141A7> The curved portion 141A bends upward (in the +Y-axis direction) at bend 141A6 and extends up and down (in the Y-axis direction) to bend 141A7. Sections 141A6-141A7 are parallel to the vertical direction. The vertical lengths of sections 141A6-141A7 are, for example, equal to the vertical lengths of sections 141A2-141A3 and sections 141A4-141A5. Sections 141A6-141A7 are located inside the wiping region 114A and the second antifogging region 112.

[0095] <Sections 141A7-141A8> Curved portion 141A bends diagonally upward to the left at bend 141A7 and extends in an upwardly convex arc shape to bend 141A8. The horizontal length of sections 141A7-141A8 is, for example, half or less of the horizontal length of wiring prohibited area 113.

[0096] Sections 141A7-141A8 extend in an arc shape concentric with a portion of sections 141A5-141A6 near bend 141A6. The vertical distance between sections 141A7-141A8 and sections 141A5-141A6 is constant. Sections 141A7-141A8 and sections 141A3-141A4 are located on a virtual common arc with a constant radius of curvature. Here, "constant radius of curvature" includes a case where the variation in radius of curvature is within 10 mm. Sections 141A7-141A8 are located within wiping region 114A and second antifogging region 112.

[0097] <Sections 141A8-141A9> Curved portion 141A bends upward (in the +Y-axis direction) at bend 141A8 and extends in the vertical direction (Y-axis direction) to bend 141A9. Sections 141A8-141A9 are parallel to the vertical direction. As an example, the vertical lengths of sections 141A8-141A9 are equal to the vertical lengths of sections 141A2-141A3, sections 141A4-141A5, and sections 141A6-141A7. Bent section 141A9 is located near the upper edge of wiping area 114A and is located inside wiping area 114A and second antifogging area 112.

[0098] <Sections 141A9-141A10> The first heating wire 141 bends diagonally downward to the right at bend 141A9 and extends in an upwardly convex arc shape. The first heating wire 141 extends in an upwardly convex arc shape from bend 141A9 to bend 141A10 along the upper edge of the wiping area 114A. The sections 141A9-141A10 are located inside the wiping area 114A and the second antifogging area 112.

[0099] The sections 141A9-141A10 and the sections 141A1-141A2 are located on a virtual common arc with a constant radius of curvature. The first heating wire 141 bends to the right (positive X-axis direction) at the bend 141A10 and extends linearly parallel to the X-axis direction.

[0100] <Curved portion 142A of first heating wire 142> The curved portion 142A of the first heating wire 142 is located at the center in the left-right direction of the first heating wire 142, and as an example, as shown in Figure 2, one curved portion 142A is provided on each side of the inverted T-shaped sections 141A2 to 141A9 of the first heating wire 141.

[0101] As shown in Fig. 2, the left curved portion 142A has bent portions 142A1 to 142A4, and the right curved portion 142A has bent portions 142A5 to 142A8. The left curved portion 142A and the right curved portion 142A are symmetrical with respect to the center line C. The curved portion 142A is located inside the wiping area 114A and the second defogging area 112. Note that Fig. 2 omits the linearly extending portions of the first heating wire 142 on the left and right sides in order to illustrate only the area surrounding the wiring prohibited area 113 of the overall configuration of the vehicle window glass 100.

[0102] <Sections 142A1-142A2> The first heating ray 142 starts from a linear extension within the first antifogging region 111, bends diagonally upward to the right at bend 142A1, and extends in an upwardly convex arc to bend 142A2. Sections 142A1-142A2 extend along sections 141A1-141A2 of the first heating ray 141, and the vertical spacing between sections 142A1-142A2 is equal to the vertical spacing between sections 141A1-141A2 and 141A3-141A4 of the first heating ray 141. The length of sections 142A1-142A2 is approximately half the length of sections 141A1-141A2 of the first heating ray 141. Sections 142A1-142A2 and sections 141A3-141A4 of the first heating ray 141 are located on a common imaginary arc with a constant radius of curvature. The distance along the imaginary arc between bends 142A2 and 141A4 is approximately equal to the distance along the imaginary arc between bends 141A2 and 141A9 of the first heating ray 141. Sections 142A1-142A2 are located inside the wiping area 114A and the second antifogging area 112.

[0103] <Sections 142A2-142A3> The curved portion 142A bends downward (in the -Y-axis direction) at bend 142A2 and extends up and down (in the Y-axis direction) to bend 142A3. The sections 142A2-142A3 are parallel to the up and down direction. The up and down lengths of the sections 142A2-142A3 are equal to the up and down lengths of the sections 141A2-141A3 of the first heating ray 141. The sections 142A2-142A3 are located inside the wiping area 114A and the second anti-fogging area 112.

[0104] <Sections 142A3-142A4> The curved portion 142A bends diagonally downward to the left at bend 142A3 and extends in an upwardly convex arc shape to bend 142A4. Sections 142A3-142A4 extend in an arc shape concentric with sections 142A1-142A2. The vertical distance between sections 142A3-142A4 and sections 142A1-142A2 is equal to the vertical distance between sections 141A1-141A2 and sections 141A3-141A4 of the first heating wire 141.

[0105] Sections 142A3-142A4 and sections 141A5-141A6 of the first heating ray 141 are located on a common imaginary arc with a constant radius of curvature. The distance along the imaginary arc between bends 142A3 and 141A5 is approximately equal to the distance along the imaginary arc between bends 142A2 and 141A4. Sections 142A3-142A4 are located inside the wiping area 114A and the second anti-fogging area 112. The first heating ray 142 bends to the right (positive X-axis direction) at bend 142A4 and extends linearly in the left-right direction (X-axis direction) to bend 142A5.

[0106] Sections 142A5-142A6 The curved portion 142A bends diagonally upward to the left at bend 142A5 and extends in an upwardly convex arc shape to bend 142A6. Sections 142A5-142A6 are symmetrical to sections 142A3-142A4 with respect to the center line C as the axis of symmetry.

[0107] Sections 142A5-142A6, sections 141A5-141A6 of first heating wire 141, and sections 142A3-142A4 are located on a common imaginary arc with a constant radius of curvature. The distance along the imaginary arc between bends 142A6 and 141A6 is equal to the distance along the imaginary arc between bends 142A3 and 141A5. Sections 142A5-142A6 are located inside wiping area 114A and second anti-fogging area 112.

[0108] <Sections 142A6-142A7> The curved portion 142A bends upward (in the positive Y-axis direction) at bend 142A6 and extends up and down (in the Y-axis direction) to bend 142A7. Sections 142A6-142A7 are parallel to the vertical direction. The vertical lengths of sections 142A6-142A7 are equal to the vertical lengths of sections 141A6-141A7 and sections 142A2-142A3 of the first heating ray 141. Sections 142A6-142A7 are located inside the wiping region 114A and the second antifogging region 112.

[0109] <Sections 142A7-142A8> The curved portion 142A bends diagonally downward to the right at bend 142A7 and extends in an upwardly convex arc shape to bend 142A8. Sections 142A7-142A8 extend in an arc shape concentric with sections 142A5-142A6. The vertical distance between sections 142A7-142A8 and sections 142A5-142A6 is equal to the vertical distance between sections 141A7-141A8 and sections 141A5-141A6 of the first heating wire 141.

[0110] Sections 142A7-142A8 and sections 141A7-141A8 of the first heating wire 141 are located on a common imaginary arc with a constant radius of curvature. The distance along the imaginary arc between bends 142A7 and 141A7 is equal to the distance along the imaginary arc between bends 142A2 and 141A4. Sections 142A7-142A8 are located inside the wiping region 114A and the second anti-fogging region 112. Note that curved section 142A bends to the right (positive X-axis direction) at bend 142A8, and extends rightward within the first anti-fogging region 111 to the right of bend 142A8.

[0111] <Heating by curved portions 141A and 142A and uniform heating of the entire glass plate 110> The curved portion 141A of the first heating wire 141 has sections 141A1 to 141A2 and sections 141A9 to 141A10 that extend along the arc-shaped upper edge of the wiping area 114A of the wiper, so that the upper end of the wiping area 114A of the wiper can be heated.

[0112] Furthermore, the first heating wire 141, consisting of sections 141A1-141A2, sections 141A2-141A3, and sections 141A3-141A4, surrounds three of the four sides of the wiring prohibited area 113. If the curved portion 141A is symmetrical on the left and right sides with respect to the center line C as the axis of symmetry and has a shape that does not straddle the center line C, it is difficult to surround three of the four sides of the wiring prohibited area 113.

[0113] However, in reality, sections 141A1-141A2 of curved portion 141A straddle center line C, and sections 141A2-141A9 extend downward in an inverted T-shape, thereby realizing a structure in which sections 141A1-141A4 surround three of the four sides of wiring prohibited area 113. By having sections 141A1-141A4 surround three sides of the periphery of wiring prohibited area 113 in this way, wiring prohibited area 113 of glass plate 110 can be heated evenly, and the temperature of wiring prohibited area 113 can be raised evenly to a desired temperature. This makes it possible to uniformly remove frost within wiring prohibited area 113, thereby preventing uneven frost removal.

[0114] Furthermore, since the curved portions 141A of the first heating wire 141 and the curved portions 142A of the first heating wire 142 are evenly wired inside the second anti-fogging area 112, the power density is even inside the second anti-fogging area 112. This allows the second anti-fogging area 112 to be heated evenly, and also allows the second anti-fogging area 112 and the wiring prohibited area 113 to be heated evenly. Furthermore, the temperatures of the second anti-fogging area 112 and the wiring prohibited area 113 can be raised evenly to a desired temperature, which makes the rate at which defogging is removed even and prevents uneven defogging.

[0115] In addition, the curved portions 141A and 142A within the second anti-fogging region 112, the straight portions of the first heating wire 141 other than the curved portion 141A, the straight portions of the first heating wire 142 other than the curved portion 142A, and the portion where the ten second heating wires 140A are provided (the portion within the first anti-fogging region 111) are configured so that the power density is uniform.

[0116] This allows the inside of each of the first antifogging area 111, the second antifogging area 112, and the wiring prohibited area 113 to be uniformly heated, and also allows the entire first antifogging area 111, the second antifogging area 112, and the wiring prohibited area 113 to be uniformly heated. Therefore, the temperature of the entire first antifogging area 111, the second antifogging area 112, and the wiring prohibited area 113 can be uniformly raised to a desired temperature, making the rate at which defogging is removed uniform and preventing uneven defogging.

[0117] <Calculation Example of Width of First Heat Rays 141 and 142> Here, an example of the calculation result of the width of the first heat rays 141 and 142 will be described with reference to FIGS. 4A and 4B. FIG.

[0118] 4A shows an example of calculation results for the widths of the first heating rays 141 and 142 in a comparative vehicle window glass 10. The comparative vehicle window glass 10 has a configuration in which bus bars 13 are used instead of the first bus bars 130LA, 130RA and the second bus bars 130LB, 130RB of the vehicle window glass 100 of the embodiment.

[0119] All of the 12 heating wires 140 (the first heating wires 141 and 142 and the ten second heating wires 140A) are connected to the bus bar 13 of the comparative vehicle window glass 10. Although only the bus bar 13 on the left side is shown in Fig. 4A, a similar bus bar 13 is also connected to the right side.

[0120] When the widths of the first heating rays 141 and 142 in the comparative vehicle window glass 10 were calculated, the width of the first heating rays 141 was 1.04 mm, and the width of the first heating rays 142 was 1.01 mm. Thus, in the comparative vehicle window glass 10, the widths of the first heating rays 141 and 142 both exceeded 1 mm. Although the numerical value is only slightly over 1 mm, the difference in width is clearly noticeable when actually viewed, and the field of view is obstructed.

[0121] In contrast, as shown in Figure 4B, when the widths of the first heating wires 141 and 142 were calculated for the vehicle window glass 100 of the embodiment, the width of the first heating wire 141 was 1.00 mm and the width of the first heating wire 142 was 0.97 mm. In the vehicle window glass 100 of the embodiment, by connecting the first heating wires 141 and 142 to the first bus bar 130LA and connecting ten second heating wires 140A to the second bus bar 130LB, the widths of the first heating wires 141 and 142 were both reduced by 0.04 mm, to 1 mm and 0.97 mm, respectively. Thus, it was confirmed that the vehicle window glass 100 of the embodiment can reduce the widths of the first heating wires 141 and 142 to 1 mm or less. By keeping the widths of the first heating wires 141 and 142 to 1 mm or less, a good field of view is obtained.

[0122] The calculation conditions for the widths of the first heating wires 141 and 142 in the comparative vehicle window glass 10 and the widths of the first heating wires 141 and 142 in the vehicle window glass 100 of the embodiment are as follows, by way of example: The output voltage of the vehicle's DC power supply (not shown) is 12 V, the temperature of the glass plate 110 is 20° C., the total power consumption of the first heating wires 141 and 142, the second heating wire 140A, and the bus bar 13 or the first bus bar 130LA and the second bus bar 130LB is 185 W, the power density is 450 W / m², and the power supply to the first heating wires 141 and 142 is stable. The requirement for the widths of both the first heating wires 141 and 142 to be 1.00 mm or less is a value required by many automobile manufacturers, and there are actually cases in which the heating wire width is set to 1.00 mm or less as a visibility requirement.

[0123] As described above, in the vehicle window glass 100 of this embodiment, the resistance value per unit length of the first bus bars 130LA, 130RA is equal to or less than the resistance value per unit length of the second bus bars 130LB, 130RB. This reduces the voltage drop in the first bus bars 130LA, 130RA, making it possible to increase the voltage drop in one or more first heating wires 141, 142, and thereby reducing the width of one or more first heating wires 141, 142.

[0124] Therefore, a vehicle window glass 100 with good visibility can be provided.

[0125] 5 is a plan view showing an example of the configuration of a vehicle window glass 100M according to a modified example of the embodiment. The vehicle window glass 100M has a configuration in which the first bus bars 130LA, 130RA of the vehicle window glass 100 shown in FIG. 1 are divided into two pairs of first bus bars 130LA1, 130RA1 and a pair of first bus bars 130LA2, 130RA2.

[0126] The first bus bars 130LA1, 130RA1 are positioned outboard of the first bus bars 130LA2, 130RA2 in the left-right direction, and the upper ends of the first bus bars 130LA1, 130RA1 are positioned higher than the upper ends of the first bus bars 130LA2, 130RA2. The first bus bars 130LA2, 130RA2 are positioned between the first bus bars 130LA1, 130RA1 and the second bus bars 130LB, 130RB in the left-right direction. The lower ends of the first bus bars 130LA1, 130RA1 and the lower ends of the first bus bars 130LA2, 130RA2 are connected to portions of the power supply portions 135L, 135R between the upper and lower ends of the second bus bars 130LB, 130RB.

[0127] A first first heating wire 141 is connected between the pair of first bus bars 130LA1 and 130RA1, and a second first heating wire 142 is connected between the pair of first bus bars 130LA2 and 130RA2.

[0128] The resistance value per unit length of first bus bars 130LA1 and 130RA1 is equal to or less than the resistance value per unit length of second bus bars 130LB and 130RB.Furthermore, the resistance value per unit length of first bus bars 130LA2 and 130RA2 is equal to or less than the resistance value per unit length of second bus bars 130LB and 130RB.

[0129] Here, as an example, the thicknesses of the first bus bars 130LA1, 130RA1, the first bus bars 130LA2, 130RA2, and the second bus bars 130LB, 130RB are equal. Therefore, the width (left-right width) of the first bus bars 130LA1, 130RA1 is greater than the width (left-right width) of the second bus bars 130LB and 130RB. Furthermore, the width (left-right width) of the first bus bars 130LA2, 130RA2 is greater than the width (left-right width) of the second bus bars 130LB and 130RB. Note that other configurations are similar to those of the vehicle window glass 100 shown in FIG. 1 .

[0130] This reduces the voltage drop in the first bus bars 130LA1 and 130RA1, allowing for a larger voltage drop in the first heating wire 141 and enabling a smaller width for the first heating wire 141. Similarly, this reduces the voltage drop in the first bus bars 130LA2 and 130RA2, allowing for a larger voltage drop in the first heating wire 142 and enabling a smaller width for the first heating wire 142.

[0131] Therefore, a vehicle window glass 100M with good visibility can be provided.

[0132] While exemplary vehicle window panes according to the present disclosure have been described above, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0133] The following supplementary notes are further disclosed with respect to the above embodiments. (Supplementary Note 1) A vehicle window glass including: a glass sheet for a vehicle window; and a defogger provided on the glass sheet, wherein the defogger has: a pair of first bus bars extending in the up-down direction of the glass sheet; one or more first heating wires connected between the pair of first bus bars and extending in the left-right direction of the glass sheet; a pair of second bus bars extending in the up-down direction of the glass sheet; and a plurality of second heating wires connected between the pair of second bus bars above or below the one or more first heating wires and extending in the left-right direction of the glass sheet, wherein a resistance value per unit length of the first bus bar is equal to or less than a resistance value per unit length of the second bus bar. (Supplementary Note 2) The vehicle window glass according to Supplementary Note 1, wherein the first bus bar and the second bus bar have the same thickness, and the width of the first bus bar is equal to or greater than a width of the second bus bar. (Supplementary Note 3) The vehicle window glass according to Supplementary Note 1 or 2, wherein a resistance value per unit length of the first bus bar is smaller than a resistance value per unit length of the second bus bar. (Supplementary Note 4) The vehicle window glass according to any one of Supplementary Notes 1 to 3, wherein the defogger further includes a pair of power feeding parts to which the pair of first bus bars and the pair of second bus bars are connected, and the pair of first bus bars have first ends connected to the one or more first heating wires and second ends opposite the first ends, and are connected to the pair of power feeding parts at the second ends. (Supplementary Note 5) The vehicle window glass according to Supplementary Note 4, wherein the pair of second bus bars have third ends and fourth ends opposite the third ends, and are connected to the pair of power feeding parts between the third end and the fourth end. (Supplementary Note 6) The vehicle window glass according to Supplementary Note 5, wherein the first ends of the pair of first bus bars are located higher than the third ends of the pair of second bus bars, and the one or more first heating wires are located higher than the plurality of second heating wires. (Supplementary Note 7) The vehicle window glass according to Supplementary Note 6, wherein the pair of power supply units are provided within a range from an upper end of the glass plate to two-thirds of the length of the glass plate in the up-down direction.(Supplementary Note 8) The vehicle window glass according to Supplementary Note 6, wherein the fourth ends of the pair of second bus bars are located below the pair of power supply parts. (Supplementary Note 9) The vehicle window glass according to Supplementary Note 6, wherein at least an uppermost first heat wire among the one or more first heat wires has a curved portion that is curved upward corresponding to a wiping area of ​​a wiper of the vehicle. (Supplementary Note 10) The vehicle window glass according to Supplementary Note 6, wherein the glass sheet has a wiring prohibited area, and at least one first heat wire among the one or more first heat wires has a bent portion that is bent around the wiring prohibited area. (Supplementary Note 11) The vehicle window glass according to Supplementary Note 10, wherein the at least one first heat wire has at least two bent portions, extends along three of four sides of a rectangular area that includes the wiring prohibited area, and has three sections bent at the at least two bent portions. (Supplementary Note 12) The vehicle window glass according to Supplementary Note 5, wherein the first ends of the pair of first bus bars are located lower than the third ends of the pair of second bus bars, and the one or more first heating wires are located lower than the multiple second heating wires. (Supplementary Note 13) The vehicle window glass according to Supplementary Note 12, wherein at least the lowermost first heating wire of the one or more first heating wires has a curved portion that curves downward corresponding to a wiping area of ​​a wiper of the vehicle. (Supplementary Note 14) The vehicle window glass according to Supplementary Note 12 or 13, wherein the glass sheet has a wiring prohibited area, and at least one first heating wire of the one or more first heating wires has a bent portion that bends around the wiring prohibited area. This application claims priority to Japanese Patent Application No. 2024-103810, filed on June 27, 2024, the entire contents of which are incorporated herein by reference. All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0134] REFERENCE SIGNS LIST 10 Vehicle window glass 20 Camera 100, 100M Vehicle window glass 110 Glass plate 110B Lower edge 110L Left edge 110R Right edge 110U Upper edge 111 First anti-fogging area 112 Second anti-fogging area 112A Inner edge 113 Wiring prohibited area 114 Hole 114A Wiping area 115 Shielding layer 115A Opening 115B Convex portion 120 Defogger 130LA, 130RA, 130LA1, 130RA1, 130LA2, 130RA2 First bus bar 130LB, 130RB Second bus bar 131LA, 131RA Upper end (an example of a first end) 132LA, 132RA Lower end (an example of a second end) 131LB, 131RB Upper end (an example of a third end) 132LB, 132RB Lower end (an example of a fourth end) 135L, 135R Power supply part 140 Heating wire 140A Second heating wire 141, 142 First heating wire 141A, 142A Curved part 141A1 to 141A10, 142A1 to 142A8 Bent part

Claims

1. A vehicle window glass comprising: a glass plate for a vehicle window; and a defogger provided on the glass plate, wherein the defogger has: a pair of first bus bars extending in the vertical direction of the glass plate; one or more first heating wires connected between the pair of first bus bars and extending in the left-right direction of the glass plate; a pair of second bus bars extending in the vertical direction of the glass plate; and a plurality of second heating wires connected between the pair of second bus bars above or below the one or more first heating wires and extending in the left-right direction of the glass plate, wherein the resistance value per unit length of the first bus bars is equal to or less than the resistance value per unit length of the second bus bars.

2. The vehicle window glass according to claim 1, wherein the first bus bar and the second bus bar have the same thickness, and the width of the first bus bar is equal to or greater than the width of the second bus bar.

3. The vehicle window glass according to claim 1, wherein the resistance value per unit length of the first bus bar is smaller than the resistance value per unit length of the second bus bar.

4. A vehicle window glass according to any one of claims 1 to 3, wherein the defogger further has a pair of power supply parts to which the pair of first bus bars and the pair of second bus bars are connected, and the pair of first bus bars have first ends connected to the one or more first heating wires and second ends opposite the first ends, and are connected to the pair of power supply parts at the second ends.

5. The vehicle window glass according to claim 4, wherein the pair of second bus bars have third ends and fourth ends opposite the third ends, and are connected to the pair of power supply parts between the third ends and the fourth ends.

6. A vehicle window glass according to claim 5, wherein the first ends of the pair of first bus bars are positioned higher than the third ends of the pair of second bus bars, and the one or more first heating wires are positioned higher than the multiple second heating wires.

7. A vehicle window glass according to claim 6, wherein the pair of power supply parts are provided within a range from the upper end of the glass plate to two-thirds of the length of the glass plate in the vertical direction.

8. The vehicle window glass according to claim 6, wherein the fourth ends of the pair of second bus bars are located below the pair of power supply portions.

9. A vehicle window glass as described in claim 6, wherein at least the uppermost first heating wire among the one or more first heating wires has a curved portion that curves upward corresponding to the wiping area of ​​the vehicle's wiper.

10. A vehicle window glass according to claim 6, wherein the glass plate has a wiring prohibited area, and at least one of the one or more first heating wires has a bent portion that is bent around the wiring prohibited area.

11. The vehicle window glass according to claim 10, wherein the at least one first heating wire has at least two bent portions, extends along three of the four sides of the rectangular area that includes the wiring prohibited area, and has three sections that are bent at the at least two bent portions.

12. A vehicle window glass according to claim 5, wherein the first ends of the pair of first bus bars are positioned lower than the third ends of the pair of second bus bars, and the one or more first heating wires are positioned lower than the plurality of second heating wires.

13. A vehicle window glass as described in claim 12, wherein at least the lowermost first heating wire among the one or more first heating wires has a curved portion that curves downward corresponding to the wiping area of ​​the wiper of the vehicle.

14. A vehicle window glass according to claim 12, wherein the glass plate has a wiring prohibited area, and at least one of the one or more first heating wires has a bent portion that is bent around the wiring prohibited area.

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