Vehicular glass

Abstract

In this vehicular glass, a plurality of heat wires extending in a prescribed direction are routed side by side in a glass plate. The glass plate has a first region and a second region which is adjacent to the first region and to which an on-vehicle device is attached. The plurality of heat wires routed in the first region are collectively guided in the second region where the number of the heat wires is lesser than that in the first region.

Description

Vehicle glass

[0001] The present invention relates to vehicle glass.

[0002] BACKGROUND ART Window glass such as the rear window of an automobile is equipped with a defogger that removes fogging and frost by passing an electric current through a plurality of heating wires arranged at intervals to generate heat.

[0003] Patent Document 1 discloses that in a window glass for a vehicle equipped with a defogger, a heating wire is routed around an information-transmitting area on the glass plate where on-board equipment such as a camera or sensor is attached and external information is transmitted.

[0004] Japanese Patent Application Publication No. 2023-23392

[0005] However, if the heating wire is extended and routed around the information transmission area as in the window glass described in Patent Document 1, the resistance value of the heating wire increases by the amount of the extended wire length, the current flowing through the routed heating wire decreases, and the heat generation performance decreases. Also, if the routed heating wire is made thicker so that the resistance value does not change, the current flowing through the routed heating wire can be made the same current value, but the amount of heat generated per unit length of the routed heating wire decreases by the amount of the extended wire length, and the heat generation performance also decreases.

[0006] Thus, simply extending the heat wire and routing it around the information transmitting area reduces the heat generating performance of the heat wire, and reduces the defogging performance for removing fogging and frost from the information transmitting area.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vehicle window glass that is capable of improving defogging performance by preferentially heating a specific region.

[0008] The present invention has the following configuration: A vehicle glass having a plurality of heating wires arranged side by side on a glass sheet, the heating wires extending in a predetermined direction, the glass sheet having a first region and a second region adjacent to the first region in which on-vehicle equipment is attached, and in the second region, the plurality of heating wires arranged in the first region are concentrated and routed in a number less than the number in the first region.

[0009] According to the present invention, it is possible to provide a vehicle window glass that is capable of improving defogging performance by preferentially heating a specific region.

[0010] Fig. 1 is a plan view of a vehicle glass according to this embodiment. Fig. 2 is an enlarged view of part A in Fig. 1. Fig. 3 is a schematic wiring diagram of a defogger. Fig. 4 is a circuit diagram of part B in Fig. 3. Fig. 5 is an enlarged view of part A in Fig. 1 for explaining a modified example.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Fig. 1 is a plan view of a vehicle glass 100 according to this embodiment.

[0012] As shown in Fig. 1, a vehicle glass 100 according to this embodiment has a glass plate 10 that serves as a window glass for a vehicle such as an automobile, and the glass plate 10 is provided with a defogger 30. This example illustrates a case where the vehicle glass 100 is used as a window glass for a rear window of a vehicle.

[0013] The glass plate 10 is generally rectangular in plan view and has an upper edge 11, a lower edge 13, and left and right side edges 15, 15. The glass plate 10 is not limited to a square or a rectangle, and may have any shape, such as a trapezoid or a parallelogram, and each side may have a curved shape. In this example, the glass plate 10 is generally trapezoidal in shape, with both side edges 15 sloping downward. Furthermore, both sides of the lower edge 13 of the glass plate 10 are curved, and the corners between the upper edge 11 and both side edges 15 are curved. The first glass plate 10 is not limited to a flat shape, and may have a curved shape that bulges outward toward the vehicle exterior. The glass plate 10 may be a single glass plate or a laminated glass having an intermediate layer sandwiched between a pair of glass plates.

[0014] The glass plate 10 has a light-shielding film 21. This light-shielding film 21 is made of a dark-colored ceramic print, for example, black, and is printed on the interior surface of the glass plate 10. The light-shielding film 21 is provided along the outer edge of the glass plate 10. By providing this light-shielding film 21, the adhesive portions of the glass plate 10 to the window frame of the vehicle are covered by the light-shielding film 21 so that they cannot be seen from outside the vehicle.

[0015] The glass plate 10 is provided with a wiper mounting portion 17 at the center of the lower part, and a rotation shaft (not shown) of a rear wiper is disposed at this wiper mounting portion 17. The light-shielding film 21 has an upwardly bulging portion at the center in the vehicle width direction along the lower edge 13 of the glass plate 10, and the wiper mounting portion 17 is disposed at this upwardly bulging portion of the light-shielding film 21.

[0016] 2 is an enlarged view of portion A in FIG. 1 . As shown in FIG. 2 , the glass plate 10 has a first region A1 and a second region A2 adjacent to each other. The first region A1 is a region inside the light-shielding film 21. The second region A2 is provided in the upper center of the glass plate 10 and adjacent to the first region A1. The upper center of the glass plate 10 is covered with the light-shielding film 21, and the second region A2 is provided in the portion covered by this light-shielding film 21. This second region A2 has an area where the light-shielding film 21 has been removed, and this area is designated as a transmissive region At. In other words, the first region A1 is a region inside the light-shielding film 21 on the glass plate 10, and the second region A2 is a region covered by the light-shielding film 21 in the upper center of the glass plate 10, including the transmissive region At.

[0017] An information detector (on-board device) S is attached to the center of the upper part of the glass plate 10. This information detector S includes, for example, an imaging device such as a CCD camera or a CMOS camera, or a sensor such as a laser sensor. This information detector S detects information outside the vehicle by passing through the glass plate 10. The information detector S is attached to the interior side of the second area A2 of the glass plate 10, and detects information about the rear of the vehicle that passes through the transmission area At of the second area A2. In this example, the information detector S is an imaging device that captures an image of the rear of the vehicle that passes through the transmission area At. The image of the rear of the vehicle captured by the information detector S, which is made up of this imaging device, is displayed on a display installed inside the vehicle and can be viewed by the driver, etc.

[0018] The vehicle glass 100 is attached to the vehicle body at an angle such that the upper side is inclined toward the front of the vehicle. Therefore, the transmission area At, which transmits the image of the rear side of the vehicle to the information detector S, gradually widens downward and has a trapezoidal shape having an upper base Ata, a lower base Atb, and a pair of inclined portions Atc, Atc.

[0019] The defogger 30 provided on the glass plate 10 is an electric heating device having a defog function that removes fogging and frost from the glass plate 10 by passing an electric current through a heating wire to generate heat.

[0020] 3 is a schematic wiring diagram of the defogger 30. As shown in Fig. 1 and Fig. 3, the defogger 30 includes a plurality of (13 in this example) heating wires 31A to 31M and a pair of bus bars 33, 33. These heating wires 31A to 31M and the bus bar 33 are conductor patterns formed by printing or printing on the glass sheet 10, and are routed on the surface of the glass sheet 10 facing the interior of the vehicle.

[0021] The heating wires 31A to 31M extend in the vehicle width direction relative to the glass plate 10 and are arranged in a line at intervals in the up-down direction. The heating wires 31A to 31M are provided in order from the upper side of the glass plate 10.

[0022] The pair of bus bars 33, 33 are respectively arranged near both side edges 15, 15 of the glass plate 10 in the vehicle width direction, extend in the vertical direction, and are arranged within the range of the light-shielding film 21. Both ends of each of the heating wires 31A to 31M are integrally connected to the bus bar 33.

[0023] In the defogger 30, a voltage is applied to a pair of bus bars 33 by a power source Ba, causing a current I to flow through each of the heating wires 31A to 31M, generating heat. This heats the glass sheet 10, removing any fogging or frost from the glass sheet 10. The heating wire 31M, located at the lowest position, has a wavy portion 31Ma arranged in a wavy pattern on one side in the vehicle width direction (see FIG. 1). This wavy portion 31Ma is provided at a standby position for the wiper (not shown) attached to the wiper attachment portion 17, and the heat generated by this wavy portion 31Ma prevents the wiper from freezing on the glass sheet 10.

[0024] Among the heating wires 31A to 31M that make up the defogger 30, the upper heating wires 31A, 31B (two in this example) are consolidated into a number less than the number of heating wires 31A, 31B (two in this example). In this example, the two heating wires 31A, 31B are consolidated midway to form a single heating wire 35. As a result, the heating wire 31A is divided into divided heating wires 31AL, 31AR on both sides of the heating wire 35 in the vehicle width direction. Similarly, the heating wire 31B is divided into divided heating wires 31BL, 31BR on both sides of the heating wire 35 in the vehicle width direction.

[0025] The heating wire 35 is provided in the center in the vehicle width direction and routed in the second area A2. Specifically, the heating wire 35 is drawn from the first area A1 to the second area A2 and routed so as to surround the periphery of the transmission area At through which the information detector S acquires information.

[0026] The heating wire 35 has a pair of lower extending portions 35A, 35A, a pair of inclined extending portions 35B, 35B, and an upper extending portion 35C. The pair of lower extending portions 35A, 35A extend from connection points 37 with the dividing heating wires 31AL, 31BL and connection points 37 with the dividing heating wires 31AR, 31BR toward the center (downward) of the glass plate 10 in the up-down direction relative to the transmission region At, and further extend inward in the vehicle width direction and are drawn into the second region A2. The pair of inclined extending portions 35B, 35B extend upward and inward in the vehicle width direction from the inner end of the lower extending portion 35A opposite the connection points 37 along the inclined portion Atc of the transmission region At. The upper extending portion 35C extends in the vehicle width direction so as to connect the upper ends of the pair of inclined extending portions 35B, 35B, and is a portion that fits along the upper bottom portion Ata of the transmission area At.

[0027] Furthermore, among the heating wires 31A to 31M constituting the defogger 30, the heating wire (other heating wire) 31C adjacent to the center (below) of the transmission area At in the vertical direction of the glass plate 10 has a bulging portion 31Ca at its center in the vehicle width direction that bulges upward toward the second area A2. This bulging portion 31Ca is disposed along the lower bottom portion Atb of the transmission area At of the second area A2.

[0028] Fig. 4 is a circuit diagram of part B in Fig. 3. As shown in Fig. 4, if the resistance value of the divided heating wires 31AL, 31AR, 31BL, and 31BR arranged in the first region A1 of the two upper heating wires 31A and 31B is Ra, and the resistance value of the single heating wire 35 obtained by combining the two upper heating wires 31A and 31B is Rb, the combined resistance value R of the two heating wires 31A and 31B is given by equation (1).

[0029] R=Ra / 2+Rb+Ra / 2 =Ra+Rb...(1)

[0030] In the two heating wires 31A, 31B on the upper side of the combined resistance value R, when a current I flows through each of the heating wire segments 31AL, 31AR, 31BL, and 31BR, twice the current 2I flows through the heating wire 35. As a result, if the thickness (cross-sectional area) of the heating wire 35 is the same as the thickness (cross-sectional area) of the heating wire segments 31AL, 31AR, 31BL, and 31BR, the heat generation amount Ws within the routing range L of the heating wire 35 is given by the following equation (2).

[0031] Ws = Rb(2I) ２ …(2)

[0032] In contrast, when the two heating wires 31A, 31B are not combined, the heat generation amount Wn per heating wire in the same range as the routing range L of the heating wire 35 is expressed by the following formula (3).

[0033] Wn = (RbI ２ ) / 2 … (3)

[0034] In other words, the heat generation amount Ws in the routing range L of the heating wire 35 increases as the square of the current I compared to the heat generation amount Wn per wire when not bundled.

[0035] Therefore, as in this example, by consolidating the multiple heating wires 31A, 31B arranged in the first area A1 and routing them to the second area A2, the amount of heat generated in the heating wire 35 routed to the second area A2 can be easily increased, the second area A2 can be heated preferentially, and the defog performance for removing fogging and frost can be improved.

[0036] Here, when the length of the heating wire 35 increases due to routing in the second region A2, the resistance value Rb of the heating wire 35 increases. Therefore, in order to maintain the total power consumption Wt by making the combined resistance value R of the two heating wires 31A and 31B half the resistance value of each of the other heating wires 31C to 31M, it is necessary to increase the thickness (cross-sectional area) of the heating wire 35, for example, to reduce the resistance per unit length. In this way, even if the resistance per unit length of the heating wire 35 is reduced, in this example, the current I flowing through the heating wire 35 can be doubled, significantly increasing the heat generation amount Ws in the routing range L (see FIG. 4). As a result, the second region A2 can be heated sufficiently and evenly.

[0037] As described above, according to the vehicle glass 100 of this embodiment, the heating wires 31A, 31B arranged in the first area A1 are consolidated into one and routed to the second area A2, so that the current to the heating wire 35 routed to the second area A2 can be easily increased to increase the amount of heat generated, and the defogging performance can be improved by preferentially heating the second area A2 to remove fogging and frost.

[0038] As a result, the heat wire 35 is arranged so as to surround the periphery of the transmission area At for the information detector S to acquire information, and the heat of this heat wire 35 can efficiently remove fogging and frost from the transmission area At.

[0039] Moreover, since the heating wire 35 is routed in the vertical direction and the vehicle width direction in the second area A2, the fogging and frost in the second area A2 can be removed evenly.

[0040] Furthermore, the information detector S is attached and disposed at the upper center of the glass plate 10, and the heating wire 35, which is an aggregate of the multiple heating wires 31A, 31B, has a pair of lower extensions 35A, 35A routed toward the vertical center (downward) of the glass plate 10. In this way, the heating wire 35 extending from the connection point 37 is provided with the lower extensions 35A, 35A that are routed downward on both sides of the transmission region At and then routed toward the vertical center of the glass plate 10, thereby making it possible to efficiently heat the vertical center of the glass plate 10, from which it is desired to actively remove fogging and frost in order to ensure visibility.

[0041] Furthermore, another heat wire, heat wire 31C, is drawn from the first area A1 to the second area A2 and arranged in the vicinity of the transmission area At, so that the transmission area can be heated by the heat of this heat wire 31C, and the fogging and frost can be efficiently removed.

[0042] In the above embodiment, the heating wires 31A to 31M constituting the defogger 30 may have the same thickness, or may have different thicknesses depending on the wiring location. For example, within the range where active heating is desired, the thickness of the heating wires 31A to 31M may be made thinner to increase the resistance value per unit length.

[0043] Furthermore, the number of heating wires concentrated in the second area A2 is not limited to two, but may be three or more.

[0044] Here, a modified example in which three heating wires are combined in the second region A2 will be described. Fig. 5 is an enlarged view of part A in Fig. 1, which explains the modified example. As shown in Fig. 5, in this modified example, the upper three heating wires 31A, 31B, and 31C of the heating wires 31A to 31M that make up the defogger 30 are combined at a connection point 37 to form a single heating wire 35. As a result, the heating wire 31C is also split into split heating wires 31CL and 31CR on both sides of the heating wire 35 in the vehicle width direction.

[0045] The heating wire 35 is provided at the center in the vehicle width direction, and is routed so as to be drawn from the first area A1 to the second area A2 and surround the periphery of the transmission area At.

[0046] In this heating wire 35, a pair of lower extending portions 35A, 35A extending inward in the vehicle width direction from the connection point 37 are pulled downward from the lower bottom portion Atb, which is on the central side (lower side) in the up-down direction of the glass plate 10 with respect to the transmission region At. Then, this lower extending portion 35A is folded back at the center in the vehicle width direction of the lower bottom portion Atb of the transmission region At and connected to the inclined extending portion 35B.

[0047] According to this modification, the heat wire 35 routed around the periphery of the transmission area At is configured by aggregating three heat wires 31A, 31B, and 31C. This increases the amount of heat generated by the heat wire 35, enabling more efficient removal of fogging and frost from the transmission area At. In particular, since the transmission area At is surrounded almost entirely by the heat wire 35 with a high heat generation rate, the transmission area At can be heated in a balanced manner, thereby evenly removing fogging and frost.

[0048] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0049] As described above, this specification discloses the following: (1) A vehicle glass having a plurality of heating wires arranged side by side on a glass sheet, the heating wires extending in a predetermined direction, the glass sheet having: a first region; and a second region adjacent to the first region, in which on-vehicle equipment is attached; in the second region, the plurality of heating wires arranged in the first region are gathered together to a number fewer than the number in the first region and routed. With this vehicle glass, by gathering the plurality of heating wires arranged in the first region to a number fewer than the number in the first region and routing them to the second region, it is possible to easily increase the current to the heating wires routed to the second region, thereby increasing the amount of heat generated and improving defogging performance, which preferentially heats the second region to remove fogging and frost.

[0050] (2) In the vehicle glass according to (1), the heat rays extend in the vertical direction and the vehicle width direction in the second region. With this vehicle glass, the heat rays are routed in the vertical direction and the vehicle width direction in the second region, so that fogging and frost in the second region can be removed evenly.

[0051] (3) The vehicle glass according to (1) or (2), wherein the on-board device is an information detector that detects outside vehicle information by transmitting through the glass plate, and the heating wire is arranged in the second region so as to surround a periphery of a transparent region in the glass plate through which the information detector acquires information. With this vehicle glass, fogging or frost in the transparent region can be efficiently removed by the heat of the heating wire arranged so as to surround the periphery of the transparent region through which the information detector acquires information.

[0052] (4) The vehicle glass according to (3), wherein the information detector is disposed above the glass plate, and the concentrated heating wire has a portion that is routed toward the center of the glass plate in the vertical direction. According to this vehicle glass, by providing the concentrated heating wire with a portion that is routed toward the center of the glass plate in the vertical direction, it is possible to efficiently heat the center of the glass plate in the vertical direction, from which fogging and frost should be actively removed in order to ensure visibility.

[0053] (5) The vehicle glass according to (3) or (4), wherein the other heating wires routed in the first region are drawn into the second region and routed in the vicinity of the transmissive region. With this vehicle glass, the transmissive region can be heated by the heat of the other heating wires that are drawn from the first region to the second region and routed in the vicinity of the transmissive region, thereby efficiently removing fogging and frost.

[0054] 10 Glass plate 31A to 31M Heat ray 35 Heat ray 100 Vehicle glass A1 First area A2 Second area At Transmitting area S Information detector (on-vehicle device)

Claims

1. A vehicle glass having a plurality of heating wires arranged side by side on a glass plate, the heating wires extending in a predetermined direction, the glass plate having a first region and a second region adjacent to the first region in which on-board equipment is attached, and in the second region, the plurality of heating wires arranged in the first region are concentrated and routed in a number less than the number in the first region.

2. The vehicle glass according to claim 1, wherein in the second region, the heat rays extend in the vertical direction and in the vehicle width direction.

3. The vehicle glass according to claim 1 or 2, wherein the on-board device is an information detector that detects information outside the vehicle by transmitting through the glass plate, and the heating wire is arranged in the second area so as to surround the periphery of a transparent area in the glass plate through which the information detector obtains information.

4. A vehicle glass according to claim 3, wherein the information detector is disposed above the glass plate, and the concentrated heat rays have a portion routed toward the center of the glass plate in the vertical direction.

5. The vehicle glass according to claim 3 or 4, wherein the other heating wires routed in the first region are drawn into the second region and routed in the vicinity of the transmission region.

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