JP7797236B2 - Heater for vehicle exterior part and method for manufacturing heater for vehicle exterior part - Google Patents

Description

The present invention relates to a heater for vehicle exterior accessories that is incorporated into the vehicle exterior accessories to add snow-melting functionality to the vehicle exterior accessories, as well as a method for manufacturing the heater for vehicle exterior accessories.

In vehicles equipped with a device for transmitting and receiving electromagnetic waves such as millimeter waves, the device transmits electromagnetic waves toward the outside of the vehicle. Electromagnetic waves reflected by objects outside the vehicle, including preceding vehicles and pedestrians, are received by the device. The device then recognizes the objects using the transmitted and received electromagnetic waves, and detects the distance between the vehicle and the object, the relative speed, etc.

In the vehicle, an exterior vehicle part that is transparent to electromagnetic waves, such as an emblem or ornament, may be disposed in front of the device in the transmission direction of the electromagnetic waves.
However, when ice and snow adhere to the vehicle exterior part, electromagnetic waves are attenuated, which reduces the detection performance of the device. To address this issue, a heater for a vehicle exterior part has been proposed that can melt ice and snow while ensuring electromagnetic wave transparency (see, for example, Patent Document 1).

The above-mentioned heater for vehicle exterior accessories comprises a heater substrate and a heat generating portion formed on the heater substrate by etching or other methods using a conductive heat generating material such as copper. The heat generating portion is linear and formed so as to be wired in a fixed pattern. For example, the heat generating portion comprises multiple straight portions extending parallel to one another and multiple arc-shaped connecting portions connecting the ends of adjacent straight portions, and is wired in a serpentine wiring pattern.

With the above-mentioned heater for vehicle exterior accessories, the heat generating section generates heat when electricity is applied. Therefore, even if ice or snow adheres to the vehicle exterior accessory, the heat generated by the heat generating section melts the ice or snow, thereby suppressing the attenuation of electromagnetic waves caused by the adhesion of ice or snow.

Patent No. 6719506

However, if the portion of the vehicle exterior accessory forward of the heat-generating portion in the transmission direction is made of a material that is transparent to visible light, the heat-generating portion will be visible through the material. In this case, the heater will have a different appearance between the portion where the heat-generating portion is located and involved in heat generation, and the portion where the heat-generating portion is not located and not involved in heat generation, leaving room for improvement in terms of appearance.

A vehicle exterior heater that solves the above problem is a heater for vehicle exterior parts that is disposed in front of a device that transmits and receives electromagnetic waves in the electromagnetic wave transmission direction in a vehicle equipped with the device, and is incorporated into an electromagnetically transparent vehicle exterior part. The heater comprises an electromagnetically transparent heater substrate, and a mesh portion that is formed in a mesh shape on the heater substrate from a conductive heat-generating material and is incorporated into the vehicle exterior part in a manner that is visible from the front of the vehicle exterior part in the transmission direction. The mesh portion has multiple meshes arranged vertically and horizontally, and the multiple meshes include normal meshes that are not broken and broken meshes that are only partially broken. The mesh portion has non-conductive portions at multiple locations where multiple broken meshes are arranged, and a current path through which current flows is formed by the multiple normal meshes between adjacent non-conductive portions.

With the above configuration, current can flow through unbroken regular meshes of the mesh portion. In contrast, current flow is restricted by the broken meshes. Because multiple broken meshes are arranged in the non-conductive sections of the mesh portion, current is restricted from flowing in a direction intersecting the non-conductive sections. The current path between adjacent non-conductive sections has multiple regular meshes. Therefore, current flows along the non-conductive sections and the current path. Regular meshes through which current flows generate heat. Therefore, even if ice or snow adheres to a vehicle exterior part incorporating a heater for vehicle exterior parts (hereinafter simply referred to as "heater"), the heat generated by the regular mesh when current is applied melts the ice or snow. Electromagnetic wave attenuation caused by the adhesion of ice or snow is suppressed.

When viewing the vehicle exterior accessory from the front in the transmission direction, the heater's mesh portion is visible through the mesh. The mesh portion includes not only regular mesh that is not broken, but also broken mesh that is broken. The only difference between regular mesh and broken mesh is whether or not there is a break. Furthermore, broken mesh is only partially broken. The appearance of broken mesh is similar to that of regular mesh.

As a result, the heater has a similar appearance in areas where the regular mesh is located and is involved in heat generation, and in areas where the broken mesh is located and is not involved in heat generation, resulting in a good appearance over a wide area.

The heater for vehicle exterior parts having the above-described configuration can be manufactured, for example, by the following manufacturing method.
That is, the method for manufacturing a heater for vehicle exterior parts that solves the above-mentioned problems is a heater for vehicle exterior parts that is disposed in front of a device that transmits and receives electromagnetic waves in a transmission direction of the electromagnetic waves in a vehicle equipped with the device, and is incorporated into a vehicle exterior part that is electromagnetically transparent, the heater comprising: a heater substrate that is electromagnetically transparent; and a mesh part that is formed in a mesh shape on the heater substrate from a conductive heat-generating material and is incorporated into the vehicle exterior part in a manner that can be seen through from the front of the vehicle exterior part in the transmission direction, the mesh part comprising a plurality of meshes arranged vertically and horizontally, and a plurality of front The method for manufacturing a heater for vehicle exterior parts has a mesh that is a normal mesh that is not broken and a broken mesh that is only partially broken, and includes a foil-attaching step of attaching a foil made of a conductive heat-generating material to the heater substrate, and a patterning step of forming the mesh portion by patterning the foil that has been through the foil-attaching step, wherein in the patterning step, non-conductive portions formed by an arrangement of a plurality of the broken mesh portions are formed at a plurality of locations, and a current path through which a current flows is formed by the plurality of normal meshes between adjacent non-conductive portions.

According to the above method, a foil-attaching step and a patterning step are carried out when manufacturing a heater for a vehicle exterior part.
In the foil attachment step, a foil made of a conductive heat generating material, such as a copper foil, is attached to the heater substrate.

In the patterning process, the foil that has been through the foil lamination process is patterned. Patterning is a method of removing unnecessary portions of the foil using photolithography and optical mask processes. The patterning process forms a mesh section that has multiple meshes arranged vertically and horizontally, and includes both normal meshes that are not broken and broken meshes that are only partially broken.

In particular, during the patterning process, when forming the mesh portion, non-conductive portions consisting of an array of multiple disconnected meshes are formed in multiple locations. Then, a current path through which current flows is formed by the multiple normal meshes between adjacent non-conductive portions.

In the heater for vehicle exterior accessories, it is preferable that the current path bends at a plurality of points in the direction of current flow.
By bending the current path at multiple points in the direction of current flow as described above, the length of the current path can be increased compared to when the current path is not bent, and the resistance of the current path can be easily adjusted to a value that will generate the desired amount of heat.

In the above-mentioned heater for vehicle exterior accessories, it is preferable that a pair of electrode portions be arranged on the outer peripheral edge of the mesh portion, and that the regular mesh located at the upstream end of the current path in the current flow direction be connected to one of the electrode portions, and the regular mesh located at the downstream end be connected to the other electrode portion.

According to the above configuration, when power is supplied to the heater, current flows from one electrode portion, usually through the mesh, along the current path toward the other electrode portion.
Furthermore, since both electrode portions are disposed on the outer peripheral edge of the mesh portion, they do not affect the appearance of the mesh portion.

In the above heater for vehicle exterior accessories, the mesh portion comprises a plurality of first conductor portions arranged parallel to and spaced apart from each other, and a plurality of second conductor portions that intersect with each of the first conductor portions and are arranged parallel to and spaced apart from each other. In the area surrounded by two adjacent first conductor portions and two adjacent second conductor portions, a rectangular mesh consisting of four line segments is formed, constituting the normal mesh or the broken mesh. In the broken mesh, it is preferable that at least one of the line segments is broken at a portion of the line segment.

According to the above configuration, the rectangular mesh is made up of four line segments. A mesh in which none of the line segments are interrupted can be called a normal mesh. In a normal mesh, current can flow along each line segment. In contrast, a mesh in which at least one line segment is interrupted at a portion of that line segment is called a broken mesh. In a broken mesh, the interrupted portion restricts current from flowing along the interrupted line segments.

In the above heater for vehicle exterior accessories, the multiple meshes in the mesh portion preferably further include dummy meshes that are not involved in heat generation, and the dummy meshes are preferably located adjacent to the non-conductive portion on the opposite side of the current path.

The simulated mesh constitutes a part of the meshes in the mesh portion, and has an appearance similar to the normal meshes and the broken meshes.
By placing the simulated meshes that do not contribute to heat generation in the locations that satisfy the above conditions, the areas of the mesh portion that do not contribute to heat generation are expanded. Moreover, the simulated meshes are adjacent to non-conductive portions. Therefore, the area of the mesh portion that does not contribute to heat generation is expanded by the amount of the simulated meshes.

As a result, the area of the heater where the parts involved in heat generation and the parts not involved in heat generation have a similar appearance is further expanded, further improving the appearance of the heater and, by extension, the vehicle exterior accessory.

The above-mentioned heater for vehicle exterior accessories and the manufacturing method for the heater for vehicle exterior accessories can achieve snow-melting functionality while improving the appearance.

FIG. 2 is a partial front view showing the emblem incorporating the heater of the first embodiment together with a part of the front grille. FIG. 4 is a rear view showing a schematic configuration of the heater according to the first embodiment before a resist layer is formed. FIG. 3 is a rear view showing details of each part of the mesh portion by enlarging FIG. 2 . FIG. 4 is an enlarged partial rear view of part A in FIG. 3 . FIG. 2 is a partial cross-sectional plan view showing a part of an emblem incorporating a heater according to the first embodiment, together with a part of a millimeter-wave radar device. 5A to 5C are partial cross-sectional plan views illustrating a manufacturing process of the heater according to the first embodiment. 5A to 5C are partial cross-sectional plan views illustrating the manufacturing process of the heater according to the first embodiment. FIG. 2 is a partial cross-sectional plan view of the heater according to the first embodiment. 9 is a partial cross-sectional plan view illustrating a manufacturing process of an emblem using the heater of FIG. 8. 5 is a partial cross-sectional plan view illustrating a manufacturing process of the emblem according to the first embodiment. FIG. FIG. 10 is a rear view showing a schematic configuration of the heater according to the second embodiment before a resist layer is formed. FIG. 10 is a rear view of the heater intermediate body of the second embodiment before a resist layer is formed. FIG. 13 is an enlarged partial rear view of part B in FIG. 12 .

(First embodiment)
A first embodiment of a heater for vehicle exterior accessories, which is embodied as an emblem heater (hereinafter simply referred to as "heater") used in a vehicle emblem, will be described below with reference to FIGS. 1 to 10. FIG.

In the following description, the forward direction of the vehicle will be referred to as the front, and the reverse direction will be referred to as the rear. Furthermore, the up-down direction in the following description refers to the up-down direction of the vehicle, and the left-right direction refers to the width direction of the vehicle, which corresponds to the left-right direction when the vehicle is moving forward. Furthermore, in Figures 5 to 10, the scale of each part of the heater and emblem has been changed appropriately to ensure that each part is large enough to be recognized.

As shown in Figures 1 and 5, a millimeter-wave radar device 13 for monitoring the front of the vehicle 10 is mounted in the center of the vehicle width direction, behind the front grille 11, as a device for transmitting and receiving electromagnetic waves. Only a portion of the millimeter-wave radar device 13 is shown in Figure 5. The millimeter-wave radar device 13 has the function of transmitting millimeter waves, which are electromagnetic waves, toward the front outside the vehicle and receiving millimeter waves reflected by objects outside the vehicle. Millimeter waves are radio waves with a wavelength of 1 mm to 10 mm and a frequency of 30 GHz to 300 GHz.

In the first embodiment, as described above, the millimeter-wave radar device 13 transmits millimeter waves toward the front of the vehicle 10, and therefore the transmission direction of millimeter waves by the millimeter-wave radar device 13 is from the rear to the front of the vehicle 10. The front in the transmission direction of millimeter waves generally coincides with the front of the vehicle 10, and the rear in the same transmission direction generally coincides with the rear of the vehicle 10. Therefore, in the following description, the front in the transmission direction of millimeter waves will simply be referred to as "front," "front," etc., and the rear in the same transmission direction will simply be referred to as "rear," "rear," etc.

The thickness of the front grille 11 (see Figure 1), like that of a typical front grille, is not uniform. Furthermore, a metal plating layer may be formed on the surface of the resin base material of the front grille 11. The front grille 11 may interfere with the transmitted or reflected millimeter waves. For this reason, a window 12 is provided in front of the millimeter-wave radar device 13 in the front grille 11. In the first embodiment, the window 12 is formed in a horizontally elongated elliptical shape, with the left-right dimension being greater than the up-down dimension.

An emblem 20 is placed in the window 12 as a vehicle exterior accessory that decorates the front of the vehicle 10. The emblem 20 is formed in the shape of a horizontally elongated oval plate corresponding to the window 12, and is placed so as to cover the window 12. In other words, the emblem 20 is placed in the window 12 in an upright position, with its front surface facing the front of the vehicle 10 and its rear surface facing the rear of the vehicle 10. The front surface of the emblem 20 forms the design surface 21.

The main part of the emblem 20 is composed of the emblem main body 22. Figure 5 shows an enlarged view of a portion of the emblem main body 22. The emblem main body 22 includes an emblem substrate 23, a heater 25, and a protective portion 57, and is located in front of the millimeter-wave radar device 13.

The emblem base material 23 is formed by resin molding using a resin material that is electromagnetically transparent, i.e., capable of transmitting millimeter waves. The resin material used to form the emblem base material 23 may be transparent or opaque. In the first embodiment, the emblem base material 23 is formed from PC (polycarbonate), but it may also be formed from other resin materials, such as ABS (acrylonitrile-butadiene-styrene copolymer). The emblem base material 23 is in the shape of a horizontally elongated oval plate.

The heater 25 is located adjacent to the front of the emblem substrate 23. The heater 25 is shaped to correspond to the shape of the front surface of the emblem substrate 23 and is in close contact with the front surface. As shown in Figures 2 and 8, the heater 25 includes a heater substrate 26, an adhesive layer 29, a mesh portion 31, a pair of connecting portions (not shown), a pair of electrode portions 51, 52, and a resist layer 55. Note that Figures 2 to 4 show the heater 25 in a state before the resist layer 55 is formed.

As shown in Figures 2 and 8, the heater substrate 26 forms the framework of the heater 25. The heater substrate 26 is made of a resin material that is transparent to millimeter waves and visible light and has excellent heat resistance and shrinkage resistance (dimensional stability). In the first embodiment, the heater substrate 26 is made of PET (polyethylene terephthalate) and is transparent. The heater substrate 26 includes a main body 27 having a horizontally elongated oval shape and an extension 28 extending from the lower outer edge of the main body 27. Although not shown, the extension 28 is bent rearward along the lower edge of the emblem substrate 23 (see Figure 5). The extension 28 is disposed within a socket portion located rearward of the emblem substrate 23.

The adhesive layer 29 functions to adhere the mesh portion 31 to the heater substrate 26, and is formed over the entire rear surface of the heater substrate 26 (main body portion 27 and extension portion 28). The adhesive layer 29 can be, for example, a transparent film-like optical adhesive sheet known as OCA (optical clear adhesive).

Note that "transparent" in the heater substrate 26 and adhesive layer 29 includes colorless transparency as well as colored transparency (colored transparency). This also applies to the resin sheet 58 and adhesive layer 59 of the protective portion 57, which will be described later.

The mesh portion 31 is formed on the rear surface of the main body portion 27, in a horizontally elongated elliptical region slightly spaced radially inward from the outer peripheral edge of the main body portion 27, via the adhesive layer 29.
As shown in Figure 3, the mesh portion 31 includes a plurality of first conductor portions 32 arranged parallel to each other and spaced apart, and a plurality of second conductor portions 33 that intersect with each first conductor portion 32 and are arranged parallel to each other and spaced apart.

In the first embodiment, the multiple first conductor portions 32 extend in the vertical direction while being spaced apart and parallel to each other in the horizontal direction. The multiple second conductor portions 33 extend in the horizontal direction while being spaced apart and parallel to each other in the vertical direction. The first conductor portions 32 and the second conductor portions 33 are perpendicular to each other. The spacing between adjacent first conductor portions 32 is uniform, and the spacing between adjacent second conductor portions 33 is uniform. The line width of each of the first conductor portions 32 and second conductor portions 33 is approximately 20 μm.

As shown in Figure 4, a rectangular mesh consisting of two line segments 34 and two line segments 36 is formed in the area surrounded by two adjacent first conductor portions 32 and two adjacent second conductor portions 33. In the first embodiment, the four line segments 34, 36 are set to the same length (approximately 4000 μm), and the mesh forms a square.

The meshes are arranged continuously both vertically and horizontally. The line segment 34 of a given mesh is common to the line segment 34 of the mesh adjacent to it in the left-right direction. Furthermore, the line segment 36 of a given mesh is common to the line segment 36 of the mesh adjacent to it in the up-down direction.

The multiple meshes include normal meshes 38, which are not broken, and broken meshes 41, which are only partially broken. In the normal mesh 38, none of the line segments 34, 36 are broken. In contrast, in the broken mesh 41, at least one of the line segments 34, 36 is broken in part. The length of the broken portion (hereinafter referred to as the "broken portion 42") is, for example, approximately 100 μm. In the broken mesh 41, which includes line segments 34, 36 with broken portions 42, the broken portions 42 restrict current from flowing along those line segments 34, 36.

As shown in Figures 2 to 4, the mesh portion 31 has multiple non-conductive portions 43. Each non-conductive portion 43 is formed by arranging the broken mesh 41 in the left-right or up-down direction so that it forms a line.

In the non-conductive portions 43 extending in the left-right direction, all of the line segments 34 except for the line segments 34 at both ends have a dividing portion 42. The line segments 34 at both ends may or may not have a dividing portion 42.

In the non-conductive portions 43 (see Figure 4) extending in the vertical direction, all of the line segments 36 except for the line segments 36 located at both ends have a dividing portion 42. The line segments 36 at both ends may or may not have a dividing portion 42.

In Figure 2, the non-conductive portions 43 are represented by thick solid lines. Furthermore, in Figures 3 and 4, the non-conductive portions 43 are represented by dashed-dotted lines. This is because the divided portions 42 in the broken mesh 41 are very small and difficult to represent in a drawing. Therefore, by using thick solid or dashed-dotted lines as described above, it is possible to clearly show that the divided portions 42 are located on the line segments 34 and 36, and that the non-conductive portions 43 are formed by these broken meshes 41. Therefore, the thick solid or dashed-dotted lines are merely imaginary lines, and do not actually exist.

As shown in FIG. 2 , four of the non-conductive portions 43 extend in the left-right direction while being spaced apart from one another in the up-down direction. Two of the non-conductive portions 43 extend in the up-down direction while being spaced apart from one another in the left-right direction. As described above, in each non-conductive portion 43, all of the line segments 34, 36 that intersect with the extension direction of the non-conductive portion 43 have dividing portions 42, so that current is prevented from crossing (orthogonal to) the non-conductive portion 43. Current can flow along the non-conductive portion 43. For these reasons, by devising an arrangement of the non-conductive portions 43, the regular mesh 38 between adjacent non-conductive portions 43 forms a current path 44 along which the current flows while changing direction multiple times. The current path 44 is illustrated by a thick, two-dot chain line in FIGS. 2 and 3 .

As shown in Figures 2 and 3, the multiple meshes further include multiple simulated meshes 45 that are not involved in heat generation. The simulated meshes 45 are arranged adjacent to the opposite side of the current path 44, sandwiching the non-conductive portion 43. For example, in Figures 2 and 3, the mesh above the topmost non-conductive portion 43 extending in the left-right direction and the mesh below the bottommost non-conductive portion 43 extending in the left-right direction are composed of simulated meshes 45. Also, in Figures 2 and 3, the mesh to the left of the leftmost non-conductive portion 43 extending in the up-down direction and the mesh to the right of the rightmost non-conductive portion 43 extending in the up-down direction are composed of simulated meshes 45.

The simulated mesh 45 may have a configuration similar to that of the normal mesh 38. That is, in the simulated mesh 45, none of the line segments 34, 36 may be broken. The simulated mesh 45 may also have a configuration similar to that of the broken mesh 41. That is, in the simulated mesh 45, at least one line segment 34, 36 may be partially broken.

The pair of connection portions are spaced apart and formed on the rear surface of the extension portion 28 via an adhesive layer 29. A connector pin is fixed to each connection portion by soldering, adhesive, crimping, or other fixing means. Both connection portions and both connector pins are positioned together with the extension portion 28 within the socket portion, which is located behind the emblem base material 23.

One electrode portion 51 is formed on the rear surface of the left portion of the outer periphery of the main body portion 27 via an adhesive layer 29. The electrode portion 51 is located on the outer periphery of the mesh portion 31 and functions as a positive electrode. The lower end of the electrode portion 51 is connected to one of the connection portions of the extension portion 28. The upper portion of the electrode portion 51 is connected to the normal mesh 38 located at the upstream end of the current path 44.

The other electrode portion 52 is formed on the rear surface of the right portion of the outer periphery of the main body portion 27 via an adhesive layer 29. The electrode portion 52 is located on the outer periphery of the mesh portion 31 and functions as a negative electrode. The lower end of the electrode portion 52 is connected to the other connection portion of the extension portion 28. A portion of the electrode portion 52 is connected to the normal mesh 38 located at the downstream end of the current path 44.

The line width of each electrode portion 51, 52 is set wider than the line width of the first conductor portion 32 and the second conductor portion 33. This is to prevent the electrode portions 51, 52 from generating heat by increasing the resistance of the electrode portions 51, 52, which would otherwise prevent the mesh 38 from generating heat.

The mesh portion 31, the pair of connecting portions, and the pair of electrode portions 51, 52 are formed from a foil made of a conductive heat generating material, and in the first embodiment, from a copper foil.
As shown in FIG. 8, the resist layer 55 is made of an insulating material and is formed on the adhesive layer 29 around the mesh portion 31 to cover the mesh portion 31 .

As shown in FIG. 5, a binder layer 56 is formed between the resist layer 55 and the emblem base material 23. When heat is transferred from the molten resin material and pressure is applied during resin molding of the emblem base material 23, the binder layer 56 exerts adhesive force, thereby enhancing the adhesion between the emblem base material 23 and the resist layer 55. The binder layer 56 is formed from a resin material that can bond with the emblem base material 23, such as PMMA (polymethyl methacrylate) or the above-mentioned ABS.

The protective portion 57 is sheet-shaped and includes a resin sheet 58 and an adhesive layer 59. It is positioned adjacent to the front of the heater substrate 26. The protective portion 57 serves to protect the heater 25, and in particular the mesh portion 31, from any impact that may be applied to the emblem 20 from the front.

Like the emblem substrate 23, the resin sheet 58 is made of a millimeter-wave transparent resin material. The resin sheet 58 is made of a transparent resin material, which in this embodiment is PC. The resin sheet 58 is shaped to correspond to the shape of the front surface of the heater substrate 26.

The adhesive layer 59 is formed from the same OCA as the adhesive layer 29. The adhesive layer 59 is located between the resin sheet 58 and the heater substrate 26, and adheres the resin sheet 58 to the front surface of the heater substrate 26 in close contact.

In addition to the emblem main body 22, the emblem 20 also has an attachment portion (not shown). As shown in Figures 1 and 5, the emblem 20 is placed upright inside the window portion 12 and attached to the front grille 11 or the vehicle body at the attachment portion.

Furthermore, by connecting the connector of the external device to the socket portion, the pair of electrodes 51, 52 are electrically connected to the external device via the connection portion and connector pin.

Next, the operation of the first embodiment configured as described above will be described together with a method for manufacturing the heater 25. The effects resulting from the operation will also be described.
The heater 25 is manufactured through a foil attachment step, a patterning step, and a resist layer formation step.

<Foiling process>
As shown in FIG. 6 , in the foil pasting process, the OCA is attached to the rear surface of the main body portion 27 and the rear surface of the extension portion 28 , thereby forming an adhesive layer 29 over the entire rear surface of the heater base material 26 .

The heater substrate 26 with the adhesive layer 29 formed thereon and the foil 61 made of conductive heat-generating material, in this case copper foil, are pressed toward each other using a roller or the like. The foil 61 is attached to the heater substrate 26 by the adhesive layer 29.

<Patterning process>
6 and 7, the foil 61 is subjected to patterning processing. The patterning processing is a processing method for removing unnecessary portions of the foil 61 by performing photolithography and optical mask processes.

By patterning, a pair of connection portions is formed on the rear surface of the extension portion 28 via the adhesive layer 29. Furthermore, a pair of electrode portions 51, 52 and a mesh portion 31 having multiple meshes arranged continuously both vertically and horizontally are formed on the rear surface of the main body portion 27. When forming the mesh portion 31, the multiple meshes formed include normal meshes 38 that are not broken, broken meshes 41 that are only partially broken, and simulated meshes 45.

Furthermore, in the patterning process, when forming the mesh portion 31, non-conductive portions 43 are formed in multiple locations, each consisting of an array of multiple disconnected meshes 41. Current paths 44 are formed by multiple normal meshes 38 between adjacent non-conductive portions 43 (see Figure 2).

<Resist layer forming step>
In the resist layer forming step, as shown in FIG. 8, a solder resist or the like is applied to the adhesive layer 29 around the mesh portion 31, thereby forming a resist layer 55 that covers the mesh portion 31.

In this manner, the heater 25 is produced, which includes the heater substrate 26, the adhesive layer 29, the mesh portion 31, the pair of connecting portions, the pair of electrode portions 51, 52, and the resist layer 55.
The emblem 20 incorporating the heater 25 is formed through the following emblem base material molding process and coating process.

<Emblem base material molding process>
In the emblem substrate molding process, although not shown, the heater 25 is pre-shaped to have a shape that generally corresponds to the shape of the front surface of the emblem substrate 23. For this pre-shaping, for example, a jig (not shown) is used whose front surface has a shape generally similar to the shape of the front surface of the emblem substrate 23. The heater 25 is heated and softened, and is placed in contact with or close to the jig. The softened heater 25 is vacuum-sucked toward the jig. The heater 25 is then brought into close contact with the front surface of the jig, and is pre-shaped to have a shape that generally corresponds to the shape of the front surface of the emblem substrate 23.

The above pre-shaping may be performed with the binder layer 56 already formed on the heater 25. Depending on the type of binder layer 56, the binder layer 56 may be formed after the above pre-shaping.

The binder layer 56 can be formed on the rear surface of the resist layer 55 by, for example, powder coating, screen printing, or the like.
As described above, the emblem substrate 23 is insert-molded using the heater 25, which has been pre-shaped and on which the binder layer 56 is formed, as an insert member. For this insert molding, a mold 60 including a fixed mold 62 and a movable mold 63 is used, as shown in FIG. 9 . The movable mold 63 is separated from the fixed mold 62, and the heater 25 on which the binder layer 56 is formed is placed in the fixed mold 62. When the mold 60 is clamped, a cavity 64 is formed between the binder layer 56 and the movable mold 63. A molten resin material for forming the emblem substrate 23, in this case PC, is injected and filled into this cavity 64. By hardening the molten resin, the emblem substrate 23 is resin-molded behind the binder layer 56, as shown in FIG. 10 . This results in an intermediate 65 in which the emblem substrate 23 is attached to the heater 25 via the binder layer 56.

<Coating process>
10 , in the covering step, the heater 25 of the intermediate body 65 is covered from the front with the protective part 57. More specifically, in the covering step, the protective part 57 is heated by far infrared rays, contact heating, or the like. The protective part 57 softened by heating is placed in contact with or close to the front surface of the heater base material 26 of the intermediate body 65.

In this state, the protective portion 57 is vacuum-sucked toward the intermediate body 65. The resin sheet 58 then adheres to the front surface of the heater substrate 26 via the adhesive layer 59, and is shaped to correspond to the shape of the front surface. The resin sheet 58 thus shaped is then attached to the front surface of the heater substrate 26 by the adhesive layer 59. The shaping may also be achieved by applying pressure with compressed air (pressure forming).

As a result, the desired emblem 20 is obtained, in which the protective portion 57 and the intermediate body 65 are integrated, as shown in FIG.
The emblem 20 thus obtained is attached to the front grille 11 or the vehicle body at the attachment portion. In this emblem 20, the protective portion 57 is located forward of the heater 25. The resin sheet 58 of the protective portion 57 is formed to a shape corresponding to the shape of the front surface of the heater substrate 26 and covers the heater substrate 26 from the front. The protective portion 57 absorbs impact when a flying stone or the like strikes the emblem main body 22 from the front. The protective portion 57 protects the heater 25, and in particular the mesh portion 31, from the impact caused by the collision.

The mesh portion 31 of the heater 25 is made up of a plurality of meshes arranged continuously both vertically and horizontally. Each mesh is made up of two line segments 34 and two line segments 36.
4, in the normal mesh 38, none of the line segments 34, 36 are separated. In the normal mesh 38, current can flow along each of the line segments 34, 36.

In contrast, in the broken wire mesh 41, at least one of the line segments 34, 36 is partially broken. The broken line segments 34, 36 have a broken portion 42 in part. In the broken wire mesh 41, the broken portion 42 restricts the flow of current along the line segments 34, 36.

As shown in Figures 2 to 4, multiple broken meshes 41 are arranged in the non-conductive portions 43 of the mesh portion 31. This prevents current from flowing in a direction that crosses the non-conductive portions 43.

In particular, in the first embodiment, in each non-conductive portion 43, all of the multiple line segments 34, 36, except for the line segments 34, 36 located at both ends, have a dividing portion 42. Therefore, in each non-conductive portion 43, more line segments 34, 36 are restricted from flowing current than if only some of the multiple line segments 34, 36, excluding the line segments 34, 36 located at both ends, had a dividing portion 42. As a result, current is further restricted from flowing in a direction intersecting each non-conductive portion 43.

The current path 44 between the adjacent non-conducting portions 43 has a plurality of normal meshes 38. Therefore, the current flows along the non-conducting portions 43 and the current path 44.
When ice or snow adheres to the design surface 21 of the emblem 20, power is supplied from an external device to the heater 25 via the connector pin, the connection portion, and the electrodes 51 and 52. Current flows from one electrode 51 through the normal mesh 38 toward the other electrode 52, bending along the current path 44, i.e., changing direction. The normal mesh 38 through which the current flows generates heat. Because the current flows through multiple normal meshes 38 between adjacent non-conducting portions 43, a wide area of the mesh portion 31 generates heat. As shown in FIG. 5 , some of this heat is transferred to the design surface 21 of the emblem 20 via the adhesive layer 29, the heater substrate 26, and the protective portion 57. This heat melts the ice or snow adhering to the design surface 21. This suppresses attenuation of millimeter waves due to ice or snow, thereby preventing a decrease in the detection performance of the millimeter-wave radar device 13 caused by the adhesion of ice or snow.

When the emblem 20 is viewed from the front, the mesh portion 31 can be seen through because the components located in front of it are transparent. The mesh portion 31 includes not only unbroken normal mesh 38, but also broken mesh 41. In the normal mesh 38, none of the four line segments 34, 36 have a dividing portion 42. In contrast, in the broken mesh 41, each of the two line segments 34 (36) has a dividing portion 42 in part. The only difference between the normal mesh 38 and the broken mesh 41 is the presence or absence of a dividing portion 42. Furthermore, the length of each dividing portion 42 is short. The appearance of the broken mesh 41 is similar to that of the normal mesh 38.

As a result, the heater 25 has a similar appearance in areas where the regular mesh 38 is located and is involved in heat generation, and in areas where the broken mesh 41 is located and is not involved in heat generation. The mesh pattern appears uniform over a wide area of the mesh portion 31. This improves the appearance of the heater 25, and ultimately the emblem 20.

Furthermore, in the first embodiment, in addition to the normal mesh 38 and the broken mesh 41, the mesh portion 31 has dummy mesh 45, which are not involved in heat generation, at the top, bottom, left side, and right side of the mesh portion 31. The dummy mesh 45 constitutes part of the multiple meshes in the mesh portion 31 and has an appearance similar to the normal mesh 38 and the broken mesh 41.

The simulated mesh 45 is located adjacent to the opposite side of the current path 44, sandwiching a specific non-conductive portion 43. As described above, the simulated mesh 45 is not involved in heat generation. Therefore, the simulated mesh 45 expands the area of the mesh portion 31 that is not involved in heat generation. Furthermore, the simulated mesh 45 is adjacent to the non-conductive portion 43. Therefore, the mesh portion 31 is expanded to the opposite side of the current path 44, sandwiching the non-conductive portion 43, by the amount of the simulated mesh 45.

As a result, the area of the heater 25 where the parts involved in heat generation and the parts not involved in heat generation have a similar appearance is further expanded, further improving the appearance of the heater 25 and, ultimately, the emblem 20.

Furthermore, the line width of each mesh segment 34, 36 is narrow, at approximately 20 μm. The size of each mesh segment, i.e., the length of each mesh segment 34, 36, is long, at approximately 4000 μm. Therefore, none of the mesh segments are visible, which also improves the appearance of the heater 25 and, ultimately, the emblem 20.

The line width of the electrode portions 51, 52 is wider than the line width of the line segments 34, 36 in the mesh. However, because both electrode portions 51, 52 are positioned on the outer periphery of the mesh portion 31, they do not significantly affect the appearance of the mesh portion 31. This also contributes to improving the appearance of the heater 25.

When millimeter waves are transmitted from the millimeter-wave radar device 13 shown in Figure 5, the millimeter waves pass through various parts of the emblem main body 22. The transmitted millimeter waves are reflected by objects in front of the vehicle, including preceding vehicles and pedestrians, and then pass through the emblem main body 22 again and are received by the millimeter-wave radar device 13. The millimeter-wave radar device 13 recognizes objects based on the transmitted and received millimeter waves, and detects the distance and relative speed between the vehicle 10 and the object, etc.

In the heater 25, millimeter waves pass through the mesh of the mesh portion 31 and the heater substrate 26. As described above, the line width of each line segment 34, 36 in the mesh is narrow, so they are unlikely to impede the transmission of millimeter waves. Furthermore, because the length of each line segment 34, 36 is long and the mesh is large, the mesh is unlikely to impede the transmission of millimeter waves.

In addition to the above, the first embodiment also provides the following effects.
(1) As a type of heater, unlike the first embodiment, a type in which a heater wire is wired on a heater substrate is known. The heater wire includes a linear heating portion made of a conductive heating material such as copper, and a covering portion made of a resin material such as urethane resin that covers the heating portion.

When manufacturing the heater of this type, a heater wire is laid on a heater substrate, but this process is difficult and increases the manufacturing cost of the heater.
In contrast to this, in the first embodiment, a foil 61 made of a conductive heat-generating material such as copper is attached to the heater substrate 26 with an adhesive layer 29, and the foil 61 is patterned to form the mesh portion 31, the electrodes 51, 52, etc. Therefore, compared to when a heater wire is laid on the heater substrate, the mesh portion 31, etc. can be formed easily and at low cost.

(2) The amount of heat generated when current flows through the current path 44 is proportional to the amount of power. The amount of power is proportional to the square of the voltage and inversely proportional to the resistance. In a vehicle, the voltage is constant. On the other hand, the resistance is proportional to the length and resistivity, and inversely proportional to the cross-sectional area (width x thickness). Resistivity is determined by the material. It is difficult to reduce the thickness of the line segments 34 and 36 by etching. Therefore, to obtain the required amount of heat at a constant voltage, the width of the line segments must be increased and the length of the current path 44 must be increased.

In this regard, in the first embodiment, current can flow through the normal mesh 38 that is not broken, but is restricted from flowing through the broken mesh 41 that is broken.
Here, if the mesh portion 31 were made up of only the normal mesh 38, the current would flow straight from one electrode portion 51 to the other electrode portion 52, and the current path 44 would become short.

In contrast, in the first embodiment, the current path 44 is bent at multiple locations by devising an arrangement of the non-conducting portions 43. This bending increases the length of the current path 44. This makes it easier to design the resistance of the current path 44 to a value that will achieve the desired amount of heat generation.

(3) When designing the current path 44, it is only necessary to determine which of the multiple meshes that make up the mesh portion 31 will be the disconnected meshes 41 and which line segments 34, 36 will be disconnected. This allows for a high degree of freedom in the design of the current path 44, allowing for flexible design.

Second Embodiment
Next, a second embodiment of the heater for vehicle exterior accessories, which is a heater used in a vehicle emblem, will be described with reference to Figures 11 to 13. Note that in Figures 11 and 12, the meshes (normal meshes 38, broken meshes 41, and dummy meshes 45) in the mesh portion 31 are not shown.

The millimeter-wave radar device 13 of the second embodiment (see Figure 5) transmits radio waves while varying the frequency band, for example, from 76 GHz to 77 GHz, with a center frequency of 76.5 GHz and a width of approximately 1 GHz.

In the second embodiment, the heater base 26 includes a main body 27 having a horizontally elongated oval shape and a pair of extensions 28 extending from the lower portion of the outer periphery of the main body 27 .
13, in the second embodiment, the mesh portion 31 is configured with smaller meshes than in the first embodiment. In other words, the length of the line segments that make up the mesh is set shorter in the second embodiment than in the first embodiment. As the mesh becomes finer, it becomes more difficult for millimeter waves to pass through.

In the second embodiment, the mesh section 31 not only has multiple meshes, but also multiple transmission assisting sections 70 that are regularly arranged vertically and horizontally and overlap the meshes. Each transmission assisting section 70 has a heat-generating function and is not very noticeable. In addition, it has a function similar to a bandpass filter, passing radio waves in a specific frequency band and suppressing the passage of radio waves of frequencies outside that band. Each transmission assisting section 70 is configured so that its passband is, for example, 76 GHz to 77 GHz.

Each of the transmission assisting portions 70 is also formed by patterning.
11 and 13, similarly to the first embodiment, the mesh portion 31 in the second embodiment includes a plurality of normal meshes 38, a plurality of broken meshes 41, and a plurality of simulated meshes 45 (not shown). In the second embodiment, the simulated meshes 45 are located on both the left and right sides of the mesh portion 31. Specifically, the simulated meshes 45 are configured by meshes to the left of the leftmost non-conductive portion 43 in the mesh portion 31 and meshes to the right of the rightmost non-conductive portion 43.

In addition, in the second embodiment, multiple non-conducting portions 43 are arranged in a manner different from that of the first embodiment, thereby forming a current path 44 through which current changes direction multiple times and flows in a manner different from that of the first embodiment. In Figure 11, the current path 44 is shown by a thick, two-dot chain line.

11 and 12, each of the pair of electrode portions 51, 52 is formed on the rear surface of the extension portion 28 of the heater base material 26 via an adhesive layer 29. As shown in FIG. 13, each of the electrode portions 51, 52 (only the electrode portion 52 is shown in FIG. 13) includes a plurality of third conductor portions 75 and a plurality of fourth conductor portions 76. The third conductor portions 75 extend in the vertical direction while being spaced apart and parallel to each other in the left-right direction, and have a wider line width than the first conductor portions 32 of the mesh portion 31. The fourth conductor portions 76 extend in the horizontal direction while being spaced apart and parallel to each other in the left-right direction, and have a wider line width than the second conductor portions 33 of the mesh portion 31. These third conductor portions 75 and fourth conductor portions 76 form a plurality of meshes that are continuously arranged vertically and horizontally.

The third conductor portion 75 is connected to the uppermost of the multiple first conductor portions 32 in the mesh portion 31 via a connection conductor portion 77. The connection conductor portion 77 is formed so that its line width gradually increases as it approaches the third conductor portion 75.

Note that Figures 12 and 13 show a heater intermediate 81 in the middle stage of manufacturing the heater 25. The heater intermediate 81 includes a heater substrate 26, a mesh portion 31, and a pair of electrode portions 51, 52. The heater intermediate 81 has a surplus heater substrate 82 around the main body portion 27 of the heater substrate 26. The surplus heater substrate 82 is connected to the main body portion 27. The outer shape of the surplus heater substrate 82 is a horizontally elongated rectangle.

The heater intermediate 81 has an excess mesh portion 83 around the mesh portion 31. The excess mesh portion 83 is formed on the excess heater substrate 82 via an excess adhesive layer 84. The outer shapes of the excess mesh portion 83 and excess adhesive layer 84 are each horizontally elongated rectangular, similar to the excess heater substrate 82. However, the excess mesh portion 83 is formed separated from the mesh portion 31 (see Figure 13).

The excess heater substrate 82, excess mesh portion 83, and excess adhesive layer 84 of the heater intermediate body 81 are trimmed at the appropriate time and separated from the main body portion 27, mesh portion 31, and adhesive layer 29 on the main body portion 27. Through this separation, the heater intermediate body 81 is formed into the shape shown in FIG. 11.

In the second embodiment, the same elements as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.
The second embodiment differs from the first embodiment in the arrangement of the non-conducting portions 43 and the shape of the current path 44. However, similar to the first embodiment, the current supplied to the heater 25 flows from one electrode portion 51 to the other electrode portion 52 while changing direction multiple times, and the normal mesh 38 through which the current flows generates heat.

Furthermore, although multiple transmission assisting portions 70 are added to ensure millimeter wave transparency, these transmission assisting portions 70 are arranged in rows and columns on the normal mesh 38 or the broken mesh 41. In other words, combinations of the transmission assisting portions 70 and the normal mesh 38 or the broken mesh 41 are arranged regularly in rows and columns. Therefore, the pattern of the above combinations appears uniform. In the second embodiment, although the visible pattern is different from that of the first embodiment, the effect of improving the appearance of the heater 25 and, ultimately, the emblem 20 is achieved.

Furthermore, in the second embodiment, the same effects as those in the first embodiment (1) to (3) above can be obtained.
The above embodiment can also be implemented as a modified example in which it is modified as follows: The above embodiment and the following modified example can be implemented in combination with each other within a range where no technical contradiction occurs.

Each of the first conductor portions 32 in the mesh portion 31 may extend in a direction that obliquely intersects with a vertical line.
Furthermore, each second conductor portion 33 in the mesh portion 31 may extend in a direction that obliquely intersects with the horizontal line.

In the mesh portion 31, the second conductor portions 33 may diagonally intersect with the first conductor portions 32. In this case, each mesh has a diamond shape.
Each mesh forming the mesh portion 31 may be formed in a rectangular shape. In this case, the length of the line segment 34 and the length of the line segment 36 are made different.

The imitation mesh 45 may be omitted from the mesh portion 31 .
The vehicle exterior part incorporating the heater 25 may be any vehicle exterior part that is disposed on a vehicle equipped with a device that transmits and receives electromagnetic waves for detecting objects outside the vehicle and that is electromagnetically transparent. In this case, the electromagnetic waves transmitted and received by the device include not only millimeter waves but also infrared waves and other electromagnetic waves.

- The device that transmits and receives electromagnetic waves to detect objects outside the vehicle may be a device for monitoring the rear, front side, or rear side, in addition to a device for monitoring the front. In this case, the vehicle exterior accessory is positioned in front of the device in the direction of transmission of the electromagnetic waves.

- The heater 25 may be incorporated into vehicle exterior parts other than emblems, such as ornaments, marks, etc.

10... Vehicle 13... Millimeter wave radar device (device)
20...Emblem (exterior vehicle part)
25...Heater (heater for vehicle exterior parts)
26: heater substrate 31: mesh portion 32: first conductor portion 33: second conductor portion 34, 36: line segments 38: normal mesh 41: disconnected mesh 43: non-conductive portion 44: current path 45: dummy mesh 51, 52: electrode portion 61: foil

Claims (6)

A heater for vehicle exterior accessories is disposed in front of a device that transmits and receives electromagnetic waves in a vehicle equipped with the device in a transmission direction of the electromagnetic waves, and is incorporated into a vehicle exterior accessory that is electromagnetically transparent,
a heater substrate having electromagnetic wave transparency; and a mesh portion formed in a mesh shape on the heater substrate using a conductive heat-generating material, and incorporated into the vehicle exterior accessory in a manner that can be seen through from the front of the vehicle exterior accessory in the transmission direction;
The mesh portion has a plurality of meshes arranged vertically and horizontally,
The plurality of meshes include normal meshes that are not broken and broken meshes that are only partially broken,
The mesh portion has non-conductive portions at a plurality of locations, each formed by an arrangement of a plurality of the disconnected meshes, and a current path through which current flows is formed by the plurality of normal meshes between adjacent non-conductive portions. The heater for vehicle exterior accessories according to claim 1, wherein the current path is bent at multiple points in the direction of current flow. a pair of electrode portions are disposed on the outer periphery of the mesh portion;
3. The heater for vehicle exterior accessories according to claim 1, wherein the regular mesh located at the upstream end of the current path in the current flow direction is connected to one of the electrode portions, and the regular mesh located at the downstream end is connected to the other of the electrode portions. the mesh portion includes a plurality of first conductor portions arranged parallel to and spaced apart from one another, and a plurality of second conductor portions arranged crossing each of the first conductor portions and parallel to and spaced apart from one another,
a rectangular mesh consisting of four line segments and constituting the normal mesh or the broken mesh is formed in an area surrounded by two adjacent first conductor portions and two adjacent second conductor portions;
4. The heater for vehicle exterior accessories according to claim 1, wherein at least one of the line segments in the broken wire mesh is broken at a portion of the line segment. The plurality of meshes in the mesh portion further include imitation meshes that are not involved in heat generation,
5. The heater for vehicle exterior accessories according to claim 1, wherein the imitation mesh is disposed adjacent to the non-conductive portion on the opposite side of the current path. A heater for vehicle exterior accessories is disposed in front of a device for transmitting and receiving electromagnetic waves in a vehicle mounted with the device in a transmission direction of the electromagnetic waves, and is incorporated into a vehicle exterior accessory that is electromagnetically transparent,
a heater substrate having electromagnetic wave transparency; and a mesh portion formed in a mesh shape on the heater substrate using a conductive heat-generating material, and incorporated into the vehicle exterior accessory in a manner that can be seen through from the front of the vehicle exterior accessory in the transmission direction;
A method for manufacturing a heater for vehicle exterior parts, wherein the mesh portion has a plurality of meshes arranged vertically and horizontally, and the plurality of meshes have normal meshes that are not broken and broken meshes that are only partially broken,
a foil-attaching step of attaching a foil made of a conductive heat-generating material to the heater substrate;
a patterning step of forming the mesh portion by patterning the foil that has been subjected to the foil pasting step,
In the patterning step, when forming the mesh portion, non-conductive portions each having a plurality of the disconnected meshes arranged therein are formed at a plurality of locations, and a current path through which current flows is formed by a plurality of the normal meshes between adjacent non-conductive portions.