JP6951674B2 - Heat-generating conductors, sheets with conductors, heat-generating plates and vehicles - Google Patents

Description

The present invention includes a heat-generating conductor, a heat-generating plate having a heat-generating conductor, a heat-generating plate having a pair of substrates and a heat-generating conductor or a sheet with a conductor arranged between the pair of substrates, and a heat-generating plate. It relates to a vehicle having this heating plate.

Conventionally, a transparent heat generating plate having a heat generating conductor has been widely used. The heating plate is used, for example, in a defroster (defrosting device) used for a window glass of a vehicle. The heat-generating plate generates heat by resistance heating when the heat-generating conductors used for these are energized (see, for example, Patent Document 1 and Patent Document 2). By raising the temperature of the heat generating conductor, the fogging of the window glass can be removed, the snow and ice attached to the window glass can be melted, or the water droplets attached to the window glass can be evaporated to improve the visibility of the occupants. Can be secured.

Japanese Unexamined Patent Publication No. 2013-173402 Japanese Unexamined Patent Publication No. 8-72674

In the conventional transparent heat generating plate, the linear conductor of the heat generating conductor extends in a certain direction to connect the pair of bus bars. However, when observing light, for example, the illumination of an oncoming vehicle through such a heating plate, a streak of light observed as if trailing a tail, that is, a light beam is observed around the illumination. The generation of such light beams can adversely affect the visibility through the window glass. As a result of diligent studies by the present inventors on this point, it was found that the light beam is generated by diffracting light (for example, illumination light of an oncoming vehicle) by a linear conductor. That is, the light beam was considered to be a phenomenon in which the diffracted light of the linear conductor was visually recognized.

Therefore, the generated light beam depends on the shape of the linear conductor, and more specifically, the shape of the contour of the linear conductor. Therefore, in the present invention, it is proposed to blur the light beam generated by devising the shape of the contour of the linear conductor.

It is also not preferable that the linear conductor is visually recognized in the heat generating plate in which the light beam is a problem. When the linear conductor is visually recognized, the transparency of the field of view through the heating plate is impaired.

The present invention has been made in consideration of the above points, and the light beam generated by devising the shape of the contour of the linear conductor while effectively avoiding the visibility of the linear conductor can be obtained. The purpose is to blur.

The heat-generating conductor of the present invention is a heat-generating conductor that generates heat when a voltage is applied.
It has a plurality of linear conductors arranged in a pattern forming a plurality of openings, and has a plurality of linear conductors.
The linear conductor includes an intersection that intersects with another linear conductor, a linear portion that extends independently of the other linear conductor, and the line between the intersection and the linear portion. It has a widening portion that widens the width of the shape conductor,
The widened portion of the linear conductor shares a part thereof with the widened portion of another linear conductor that intersects the linear conductor.
The contour of the widened portion includes a curved portion having a radius of curvature of 15 μm or more and 60 μm or less.
The distance between the centers of gravity of the adjacent openings is 250 μm or more and 1500 μm or less.
The width of the linear portion is 2 μm or more and 15 μm or less.
The thickness of the linear conductor is 1 μm or more and 30 μm or less.

In the heat generating conductor of the present invention, the length of the curved portion may be 20 μm or more.

In the heat generating conductor of the present invention, the curved portion may be a concave curve toward the opening.

In the heat-generating conductor of the present invention, the width of the widened portion may be 5 times or more and 10 times or less the width of the linear portion adjacent to the widened portion.

The sheet with a conductor of the present invention
Base film and
It includes any of the above-mentioned heat-generating conductors provided on the base film.

The heating plate of the present invention
A pair of boards and
Between the pair of substrates, any of the above-mentioned heat-generating conductors or the above-mentioned sheet with a conductor is provided.

The vehicle of the present invention includes the heating plate described above.

According to the present invention, it is possible to blur the light beam generated by devising the shape of the contour of the linear conductor while effectively avoiding the visibility of the linear conductor. Thereby, the visibility through the heat generating plate having the heat generating conductor can be improved.

FIG. 1 is a diagram for explaining one embodiment according to the present invention, and is a perspective view schematically showing a vehicle provided with a heat generating plate. In particular, FIG. 1 schematically shows an automobile provided with a front window composed of a heating plate as an example of a vehicle. FIG. 2 is a diagram showing the heat generating plate from the normal direction. FIG. 3 is a cross-sectional view of the heating plate in line III-III of FIG. FIG. 4 is a plan view showing the heat generating conductor from the normal direction thereof, and is a plan view showing an example of the heat generating conductor. FIG. 5 is a diagram showing an example of the heat generating conductor of the present invention. FIG. 6 is a diagram showing an example of a conventional heat generating conductor.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

In addition, in this specification, the terms "board", "sheet", and "film" are not distinguished from each other based only on the difference in designation. For example, "sheet with conductor" is a concept that includes members that can be called a plate or film. Therefore, "sheet with conductor" is "plate with conductor (board)" or "with conductor". It cannot be distinguished from a member called "film" only by the difference in name.

Further, the "sheet surface (plate surface, film surface)" is a target sheet-like member (plate-like) when the target sheet-like (plate-like, film-like) member is viewed as a whole and from a broad perspective. A surface that coincides with the plane direction of a member or film-like member). The normal direction used for the sheet-shaped (plate-shaped, film-shaped) member is the normal direction of the sheet-shaped (plate-shaped, film-shaped) member to the sheet surface (plate surface, film surface). Refers to.

In addition, as used in the present specification, the terms such as "parallel", "orthogonal", and "identical" and the values of length and angle that specify the shape and geometric conditions and their degrees are strictly used. Without being bound by meaning, we will interpret it including the range in which similar functions can be expected.

1 to 6 are diagrams for explaining one embodiment according to the present invention. Of these, FIG. 1 is a diagram schematically showing an automobile provided with a heating plate, FIG. 2 is a view of the heating plate viewed from the normal direction of the plate surface, and FIG. 3 is a view of FIG. 2III. It is sectional drawing of the heating plate along the −III line.

As shown in FIG. 1, an automobile 1 as an example of a vehicle has windowpanes such as a front window, a rear window, and a side window. Here, it is assumed that the front window 5 is composed of the heating plate 10. Further, the automobile 1 has a power source 7 such as a battery.

FIG. 2 shows the heating plate 10 viewed from the normal direction of the plate surface. Further, FIG. 3 shows a cross-sectional view of the heating plate 10 of FIG. 2 corresponding to lines III-III. In the example shown in FIG. 3, the heating plate 10 includes a pair of substrates 11 and 12, a sheet 20 with a conductor arranged between the pair of substrates 11 and 12, and the substrates 11 and 12 and a sheet with a conductor. It has bonding layers 13 and 14 for joining 20 and. In the examples shown in FIGS. 1 and 2, the heat generating plate 10 is curved, but in the other figures, the heat generating plates 10 and the substrates 11 and 12 are used for simplification of illustration and easy understanding. It is illustrated in a flat plate shape.

Further, as is well shown in FIG. 2, the heat generating plate 10 has a wiring portion 15 for energizing the heat generating conductor 30. In the illustrated example, the power source 7 such as a battery energizes the heat generating conductor 30 from the wiring portion 15 via the bus bar 25, and heats the heat generating conductor 30 by resistance heating. The heat generated by the heat generating conductor 30 is transferred to the substrates 11 and 12, and the substrates 11 and 12 are warmed. As a result, fogging due to dew condensation adhering to the substrates 11 and 12 can be removed. Further, when snow or ice is attached to the substrates 11 and 12, the snow or ice can be melted. Therefore, the visibility of the occupant is well secured. Although not shown, a switch is usually inserted (connected in series) between the power supply 7 and the bus bar 25 of the heat generating conductor 30. Then, the switch is closed and the heating conductor 30 is energized only when the heating plate 10 needs to be heated.

Hereinafter, each component of the heat generating plate 10, that is, the substrates 11 and 12, the bonding layers 13 and 14, and the sheet 20 with a conductor will be described.

First, the substrates 11 and 12 will be described. When the substrates 11 and 12 are used for the front window of an automobile as in the example shown in FIG. 1, it is preferable to use substrates 11 and 12 having a high visible light transmittance so as not to obstruct the view of the occupant. Examples of the materials of the substrates 11 and 12 include soda lime glass and blue plate glass. The visible light transmittance of the substrates 11 and 12 is preferably 90% or more. Here, the visible light transmittance of the substrates 11 and 12 was measured in the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, JIS K 0115 compliant product). It is specified as the average value of the transmittance at each wavelength. The visible light transmittance of this part may be lowered by coloring a part or the whole of the substrates 11 and 12. In this case, it is possible to block the direct sunlight and make it difficult to see the inside of the vehicle from the outside of the vehicle.

Further, the substrates 11 and 12 preferably have a thickness of 1 mm or more and 5 mm or less. With such a thickness, substrates 11 and 12 having excellent strength and optical characteristics can be obtained. The pair of substrates 11 and 12 may be made of the same material and may be the same, or may be different from each other in at least one of the materials and the composition.

Next, the bonding layers 13 and 14 will be described. One bonding layer 13 is arranged between the one substrate 11 and the sheet 20 with a conductor, and the one substrate 11 and the sheet 20 with a conductor are bonded to each other. The other bonding layer 14 is arranged between the other substrate 12 and the sheet 20 with a conductor, and the other substrate 12 and the sheet 20 with a conductor are bonded to each other.

As such bonding layers 13 and 14, layers made of materials having various adhesiveness or adhesiveness can be used. Further, it is preferable to use the bonding layers 13 and 14 having high visible light transmittance. As a typical bonding layer, a layer made of polyvinyl butyral (PVB) can be exemplified. The thicknesses of the bonding layers 13 and 14 are preferably 0.15 mm or more and 1 mm or less, respectively. The pair of bonding layers 13 and 14 may be made of the same material and configured in the same manner, or may be different from each other in at least one of the materials and the composition.

The heat generating plate 10 is not limited to the illustrated example, and may be provided with other functional layers expected to exhibit a specific function. Further, one functional layer may exhibit two or more functions. For example, the substrates 11 and 12 of the heat generating plate 10, the bonding layers 13 and 14, and the base film of the sheet 20 with a conductor described later will be described. At least one of 21 may be provided with some function. Examples of the functions that can be imparted to the heat generating plate 10 include an antireflection (AR) function, a hard coat (HC) function having scratch resistance, an infrared shielding (reflection) function, an ultraviolet shielding (reflection) function, and antifouling. Functions and the like can be exemplified.

Next, the sheet 20 with a conductor will be described. The conductor-attached sheet 20 has a base film 21, a pair of bus bars 25, and a heat-generating conductor 30 provided on a surface of the base film 21 facing one of the substrates 11. In the present embodiment, the sheet 20 with a conductor has substantially the same plane dimensions as the substrates 11 and 12, and is arranged over the entire heating plate 10, but the front portion of the driver's seat in the example of FIG. Etc., it may be arranged only in a part of the heat generating plate 10. Hereinafter, each component of the conductor-attached sheet 20 will be described.

The base film 21 functions as a base material that supports the heat generating conductor 30. The base film 21 is a so-called transparent electrically insulating film that transmits wavelengths in the visible light wavelength band (380 nm to 780 nm). The base film 21 may be made of any material as long as it can transmit visible light and can appropriately support the heat generating conductor 30, and may be, for example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, or cyclic. Polyolefin and the like can be mentioned. Further, the base film 21 preferably has a thickness of 0.03 mm or more and 0.20 mm or less in consideration of light transmission, appropriate supportability of the heat generating conductor 30, and the like.

In addition, "transparency" means having transparency to the extent that one side of the base film can be seen through the base film, for example, 30. It means that it has a visible light transmittance of% or more, more preferably 70% or more. The visible light transmittance is the transmittance at each wavelength when measured within the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, JIS K 0115 compliant product). Is specified as the average value of.

The bus bar 25 is electrically connected to the corresponding wiring section 15. The voltage of the power supply 7 connected to the wiring portion 15 is applied between the pair of bus bars 25. The pair of bus bars 25 are arranged so as to be parallel to each other. Further, each bus bar 25 is arranged near the outer edge portion of the conductor-equipped sheet 20.

Next, the heat generating conductor 30 will be described with reference to FIG. FIG. 4 is a plan view of the conductor-attached sheet 20 as viewed from the normal direction of the sheet surface.

The heat generating conductors 30 are arranged between the pair of bus bars 25, and are electrically connected to each other so as to connect the pair of bus bars 25. The heat generating conductor 30 is formed by linear conductors 31 arranged in a predetermined pattern. When a voltage is applied to the heat generating conductor 30 via the wiring portion 15 and the bus bar 25, the heat generating conductor 30 generates heat due to resistance heating. Then, this heat is transferred to the substrates 11 and 12 via the bonding layers 13 and 14, so that the substrates 11 and 12 are warmed.

The heat generating conductors 30 can be arranged in various patterns. As an example, in the example shown in FIG. 4, the heat generating conductor 30 is formed by arranging a plurality of linear conductors 31 in a mesh-like pattern defining a large number of openings 35. .. As shown in FIG. 5, the linear conductor 31 includes a linear portion 32, a widening portion 33 (upper right-lower left diagonal line portion in FIG. 5), and an intersection 34 (upper left-lower right diagonal line portion in FIG. 5). , Have. The linear portion 32 extends independently of the other linear conductors. On the other hand, the intersection 34 is provided at a position where it intersects with another linear conductor. The widening portion 33 widens the linear conductor 31 between the linear portion 32 and the intersecting portion 34. That is, the linear portion 32 is provided adjacent to the two widening portions 33 and connects the two widening portions 33.

The linear portion 32 may have any shape such as a straight line, a curved line, a wavy line, and a polygonal line. However, the direction in which each linear portion 32 extends and the arrangement direction of the linear portions 32 are completely set in order to prevent the diffracted light of the linear conductor 31, which will be described later, from being dispersed in all directions. It is not irregular, but preferably regular.

The intersection 34 is located within an extension of the linear portion 32. One intersection 34 included in one linear conductor 31 forms an intersection of another linear conductor 31 that intersects with the one linear conductor 31 in the entire area. That is, as is well shown in FIG. 5, each linear conductor 31 shares an intersection 34 with another linear conductor 31. In other words, one intersection 34 can be included in the two linear conductors 31.

Further, each linear conductor 31 shares a part of the widening portion 33 with the other linear conductors 31. Specifically, a part of the widening portion 33 that is not included in any of the two intersecting linear conductors 31 is shared with the other widening portion 33. In the illustrated example, at the intersection 34, the four linear portions 32 are connected at equal angles via the widening portion 33, whereby the four linear portions 32, the four widening portions 33, and the four intersecting portions are connected. A large number of lattice-shaped openings 35 surrounded by 34 are defined. Note that FIG. 5 is an enlarged view of a part of the heat generating conductor 30 of the conductor-equipped sheet 20 shown in FIG.

If the distance between the centers of gravity of the openings 35 is too large, heat generation unevenness occurs in the heat generation conductor 30. Further, if the distance between the centers of gravity of each opening 35 is too large, the linear conductor 31 may be visually recognized. From this, it is preferable that the distance D between the centers of gravity of the opening 35 shown in FIG. 5 is 1500 μm or less. Further, if the distance D between the centers of gravity of the opening 35 is too small, the transmittance deteriorates and the transparency is impaired. Therefore, the distance D between the centers of gravity of the opening 35 is preferably 250 μm or more.

The heat generating conductor 30 will be described in detail with reference to FIG. As shown in FIG. 5, the width of each linear conductor 31 is wider than that of the linear portion 32 in the widening portion 33. That is, the width w ₂ of the widening portion 33 is larger than the width w _{1 of the linear portion 32.} The width w ₂ of the widening portion 33 is preferably 5 times or more and 10 times or less the width w _{1 of the linear portion 32.} Here, the width w _{1 of the} linear portion 32 means the maximum length of the linear portion 32 in the direction orthogonal to the extending direction of the linear conductor 31, _{and the width w 2} of the widening portion 33 is. , The maximum length of the widening portion 33 at a portion that does not overlap with other linear conductors in a direction orthogonal to the extending direction of the linear conductor 31. When the width w ₂ of the widening portion 33 is 5 times or more the width w ₁ of the linear portion 32, the widening portion 33 is sufficiently wider than the linear portion 32. Further, since the width w _{2 of the widening portion 33 is 10 times or less the width w 1} of the linear portion 32, the width of the widening portion 33 is too large with respect to the linear portion 32, and the widening portion 33 is visually recognized. It is possible to prevent it from happening.

Further, the contour of the widening portion 33 of the linear conductor 31 includes a curved portion 33a having a radius of curvature of 15 μm or more and 60 μm or less at a position serving as a boundary with the opening 35. Here, the contour of the linear conductor 31 means the contour of the linear conductor 31 on the side along the plate surface of the base film 21. The curved portion 33a has a concave curve toward the opening 35 facing the curved portion 33a. The concave curve toward the opening 35 does not simply mean that it is recessed toward the intersection center of the two linear conductors forming the intersection 34, but that it is mathematically concave. do. That is, a curve concave toward the opening means that a straight line connecting arbitrary two points in the curve is located in the opening at a distance between the two points from the curve between the two points. In other words, it means that any part of the curve is located between both ends of the part and inside the straight line connecting both ends of the part. Therefore, the center of curvature that defines the radius of curvature of the curved portion 33a is not on the side of the linear conductor defined by the curved portion 33a, but on the side of the opening defined by the curved portion. Further, the length L of the curved portion 33a is 20 μm or more.

Materials for forming such a heat generating conductor 30 and a bus bar 25 include, for example, metals such as gold, silver, copper, platinum, aluminum, chromium, molybdenum, nickel, titanium, palladium, indium, and tungsten, and , One or more of alloys comprising one or more of these metals can be exemplified. The heat generating conductor 30 and the bus bar 25 may be formed of the same material, or may be formed of different materials.

The heat generating conductor 30 can be formed by using an opaque metal material as described above. On the other hand, the ratio of the region on the base film 21 not covered by the heat generating conductor 30, that is, the aperture ratio is as high as about 70% or more and 99% or less. The line width of the linear conductor 31 is about 2 μm or more and 50 μm or less. Therefore, the region where the heat generating conductor 30 is provided is transparently grasped as a whole, and the presence of the heat generating conductor 30 does not impair the transparency of the heat generating plate 10.

In the example shown in FIG. 3, the linear conductor 31 has a trapezoidal cross section as a whole. The width W of the linear conductor 31, that is, the width W along the plate surface of the base film 21 is 2 μm or more and 50 μm or less, and the height (thickness) H, that is, the normal to the plate surface of the heat generating plate 10. The height (thickness) H along the direction is preferably 1 μm or more and 30 μm or less. In the width W of the linear conductor 31, the width w ₁ of the linear portion 32 is 2 μm or more and 15 μm or less, and the width w ₂ of the widening portion 33 is 2 μm or more and 50 μm or less. According to the linear conductor 31 having such dimensions, the linear conductor 31 is sufficiently thinned, so that the heat generating conductor 30 can be effectively invisible.

Further, as shown in FIG. 3, the linear conductor 31 is a first dark color covering the surface of the conductive metal layer 36 and the conductive metal layer 36 on the side facing the base film 21. Of the surfaces of the layer 37 and the conductive metal layer 36, a second dark color layer 38 that covers the side surface facing the substrate 11 and both side surfaces may be included. The conductive metal layer 36 made of a metal material having excellent conductivity exhibits a relatively high reflectance. Then, when the light is reflected by the conductive metal layer 36 forming the linear conductor 31 of the heat generating conductor 30, the reflected light becomes visible and may obstruct the view of the occupant. Further, when the conductive metal layer 36 is visually recognized from the outside, the design property may be deteriorated. Therefore, the first and second dark-colored layers 37 and 38 cover at least a part of the surface of the conductive metal layer 36. The first and second dark color layers 37 and 38 may be layers having a lower visible light reflectance than the conductive metal layer 36, and are dark color layers such as black, for example. The dark-colored layers 37 and 38 make it difficult for the conductive metal layer 36 to be visually recognized, and a good view of the occupant can be ensured. In addition, it is possible to prevent deterioration of the design when viewed from the outside.

As described above, from the viewpoint of ensuring the transparency of the heat generating plate 10 or the visibility through the heat generating plate 10, the linear conductor 31 of the heat generating conductor 30 is a base material so as to increase the aperture ratio. It is formed on the film 21. As a result, as shown in FIG. 3, the bonding layer 13 and the base film 21 of the sheet 20 with the conductor are in a region between the uncoated portion of the linear conductor 31, that is, the adjacent linear conductors 31. Are in contact through. That is, the heat generating conductor 30 is embedded in the bonding layer 13.

By the way, as described above, when observing light, for example, lighting of an oncoming vehicle through a heating plate containing a linear conductor, a streak of light observed so as to trail a tail, that is, a light beam is around the lighting. Observed in. The generation of such light beams deteriorates the visibility through the heat generating plate. Then, as a result of repeated diligent studies, the present inventors have found that the direction in which the light beam is generated coincides with the direction in which the incident light on the heating plate is diffracted by the linear conductor. Based on the findings of the present inventors, it is possible to prevent the light beam from extending in a specific direction by making the longitudinal direction of the linear conductor 31 forming the heat generating conductor 30 irregular. However, if the arrangement of the linear conductors 31 is completely irregular, the generation of streaky bright spots, which have been regarded as light beams, can be prevented, but the diffracted light is dispersed in all parts of the heating plate to generate bright spots. However, it becomes conspicuous and obstructs the view. Further, irregular arrangement of the linear conductors 31 may increase the design load and cause in-plane heat generation unevenness, which is not preferable. Further, when visually observed in close proximity, it is easily recognized as in-plane unevenness of transmittance or reflectance. Therefore, the present inventors have conducted further diligent studies, and while maintaining the regularity of the arrangement (distribution) of the linear conductors 31, by providing the widening portion 33 on the linear conductors 31, the light beam is effectively conspicuous. It was possible to eliminate it. Hereinafter, the cause of the light beam and the method of making the light beam inconspicuous will be described.

The light beam is generated when the light transmitted through the heating plate 10 is diffracted by the linear conductor 31. That is, the observed light beam is generated when the diffraction image of the diffraction caused by the linear conductor 31 extends in a streak pattern. As long as the linear conductor 31 is arranged on the heat generating plate 10, it is not possible to prevent the diffraction image from being generated. Therefore, it is considered that the generated diffraction image has a small influence on the visibility.

The diffraction image having a small influence on the visibility through the heat generating plate 10 is an image that does not include strong streaky light recognized as a light beam. As an example of such a diffracted image, the incident light is not diffracted in a specific direction, in other words, the diffracted light is dispersed in all directions so that the streaky bright part is not recognized, thereby making the light beam inconspicuous. Is possible. However, as described above, when the diffracted light is dispersed in all directions, it is possible to prevent the streaky bright part from being recognized, but bright spots due to the diffracted light are generated at every part of the heat generating plate, and the field of view is rather visible. It interferes with. Therefore, it is conceivable to blur the streaky light recognized as a light beam to make it inconspicuous.

The shape of a diffracted image of light that passes through a structure is determined by the shape of the boundary between the light-transmitting portion and the shielded portion of the structure. For example, a diffraction image generated by a structure having a longitudinal direction, for example, a rectangular structure having a longitudinal direction, extends in a direction orthogonal to the longitudinal direction of the structure and becomes a beam of light. Therefore, if the directions orthogonal to the shape of the boundary forming one structure are different in a part of the structure, the streaks of light will be generated in different directions depending on the part, and the streaks generated by the other parts will be generated. The light will be blurred.

As a structure of such a linear conductor 31, as shown in FIG. 5, the width of the linear conductor 31 is widened in the widening portion 33, and the contour of the widening portion 33 is a curved portion 33a. Conceivable. Since the contour of the widening portion 33 becomes the curved portion 33a, the direction orthogonal to the shape of the boundary forming the structure is different in the curved portion.

The operation of the heat-generating conductor 30 of the present embodiment will be described in comparison with the conventional heat-generating conductor 130. In the conventional heat generating conductor 130 shown in FIG. 6, a plurality of linear conductors 131 extending in a straight line intersect to form a pattern. The width of the linear conductor 131 is the same as that of the linear portion 132 at the intersection 133, and is constant. In such a heat-generating conductor 130, the shape of the boundary forming the structure, that is, the direction orthogonal to the shape of the boundary of the linear conductor 131 is only the vertical direction and the horizontal direction in FIG. Therefore, in the field of view through the heat generating plate having the heat generating conductor 130, strong streaky light extending in the horizontal direction and the vertical direction is observed.

On the other hand, in the heat generating conductor 30 of the present invention shown in FIG. 5, a plurality of linear conductors 31 extending in a straight line intersect to form the same pattern as the pattern shown in FIG. However, unlike the conventional heat-generating conductor shown in FIG. 6, the width of the linear conductor 31 is widened in the widening portion 33, and the contour of the widening portion 33 is the curved portion 33a. In such a heat generating conductor 30, the shape of the boundary forming the structure, that is, the direction orthogonal to the shape of the boundary of the linear conductor 31, is different in the curved portion 33a which is a part thereof. Therefore, in the field of view through the heat generating plate 10 having the heat generating conductor 30, the streaky light extending in the horizontal and vertical directions mainly generated by the linear portion 32 is generated by the curved portion 33a of the widening portion 33. It will be blurred by the amount of streaky light.

In particular, in the present embodiment, since the radius of curvature of the curved portion 33a is 15 μm or more, the widening portion 33 can have the curved portion 33a having a sufficient length. Specifically, the length of the curved portion 33a is 20 μm or more. When the curved portion is sufficiently long, the light beam generated by the linear portion 32 is sufficiently blurred by the light beam generated by the curved portion 33a of the widening portion 33. Further, since the radius of curvature of the curved portion 33a is 60 μm or less, the light beam by the curved portion 33a of the widening portion 33 is generated around the light beam by the linear portion 32, but since it is a sufficiently weak light beam, the heat generating plate 10 It becomes difficult to observe in the field of view through.

Further, the curved portion 33a includes a concave curve toward the opening 35, and the concave curve toward the opening 35 does not protrude toward the opening 35. According to such a curved portion 33a, it is possible to make the light beam inconspicuous while effectively avoiding the widening portion 33 becoming large and easily visible. In particular, in the illustrated example, the contour line that divides the opening 35 of the widening portion 33 extends on the linear conductor side (inside) from the straight line connecting both ends between both ends thereof. According to such a widening portion 33, it is possible to effectively prevent the presence of the widening portion 33 having a function of making the light beam inconspicuous from being visually recognized.

Next, an example of a method for manufacturing the heating plate 10 will be described.

First, a dark color film that forms the first dark color layer 37 is provided on the base film 21.

Next, a metal film that forms the conductive metal layer 36 is provided on the dark color film. The metal film can be formed by a known method. For example, a method of attaching a metal foil such as copper foil, a plating method including electroplating and no-electromagnetic plating, a sputtering method, a CVD method, a PVD method, an ion plating method, or a method in which two or more of these are combined is adopted. can do.

After that, a resist pattern is provided on the metal film. The resist pattern has a shape corresponding to the heat generating conductor 30 to be formed. That is, the shape corresponds to the linear conductor 31 having the linear portion 32 and the widening portion 33. This resist pattern can be formed by patterning using a known photolithography technique.

Next, the metal film and the dark color film are etched using the resist pattern as a mask. By this etching, the metal film and the dark color film are patterned in substantially the same pattern as the resist pattern. As a result, the conductive metal layer 36 forming a part of the linear conductor 31 is formed from the patterned metal film. Further, a first dark color layer 37 that forms a part of the linear conductor 31 is formed from the patterned dark color film.

The etching method is not particularly limited, and a known method can be adopted. Known methods include, for example, wet etching using an etching solution, plasma etching, and the like. After that, the resist pattern is removed.

After that, the second dark color layer 38 is formed on the surface and the side surface of the conductive metal layer 36 opposite to the surface on which the first dark color layer 37 is provided. In the second dark color layer 38, for example, a part of the material forming the conductive metal layer 36 is subjected to a darkening treatment (blackening treatment), and a metal oxide or metal sulfide is formed from the part of the material forming the conductive metal layer 36. A second dark layer 38 made of an object can be formed. Further, the second dark color layer 38 may be provided on the surface of the conductive metal layer 36. Further, the surface of the conductive metal layer 36 may be roughened to provide the second dark color layer 38.

Through the above steps, the conductor-attached sheet 20 having the heat-generating conductor 30 is produced.

Finally, the bonding layer 13 and the substrate 11 are laminated from the side of the heat generating conductor 30, and the sheet 20 with the conductor and the substrate 11 are bonded. Similarly, the bonding layer 14 and the substrate 12 are laminated from the side of the base film 21, and the sheet 20 with the conductor and the substrate 12 are bonded. As a result, the heating plate 10 shown in FIG. 3 is produced.

As described above, according to the present embodiment, the heat generating conductor 30 is a heat generating conductor that generates heat when a voltage is applied, and is arranged in a pattern forming a plurality of openings 35. The linear conductor 31 is provided with a linear conductor 31 of the above, and the linear conductor 31 has an intersection 34 intersecting with another linear conductor 31 and a linear portion 32 and an intersection 34 extending independently of the other linear conductor 31. It has a widening portion 33 that widens the width of the linear conductor 31 between the linear portion 32 and the widening portion 33, and the contour of the widening portion 33 includes a curved portion 33a having a radius of curvature of 15 μm or more and 60 μm or less, and adjacent openings. The distance between the centers of gravity of the portions 35 is 250 μm or more and 1500 μm or less, the width W of the linear portion 32 is 2 μm or more and 15 μm or less, and the thickness H of the linear conductor 31 is 1 μm or more and 30 μm or less. According to such a heat-generating conductor 30, it is possible to blur the light beam generated in the field of view through the heat-generating conductor 30 and make it inconspicuous. Further, the heat-generating conductor 30 is transparently grasped as a whole, and the presence of the heat-generating conductor 30 does not impair the transparency. Therefore, it is possible to improve the field of view through the heat generating plate 10 having the heat generating conductor 30.

Further, in the heat generating conductor 30 of the present embodiment, the length of the curved portion 33a is 20 μm or more. According to such a heat-generating conductor 30, the ratio of the light beam generated by the curved portion 33a of the widening portion 33 to the light beam generated by the linear portion 32 is used to blur the light beam generated by the linear portion 32. It can be a sufficient ratio.

Further, in the heat generating conductor 30 of the present embodiment, the curved portion 33a has a concave curve toward the opening 35. According to such a heat-generating conductor 30, it is possible to easily manufacture the heat-generating conductor 30 in which the widened portion 33 of the linear conductor 31 is a curved portion 33a.

Further, in the heat generating conductor 30 of the present embodiment, the width w ₂ of the widening portion 33 is 5 times or more and 10 times or less _{the width w 1} of the linear portion 32 adjacent to the widening portion 33. In such a heat-generating conductor 30, while the widening portion 33 is sufficiently widened from the linear portion 32, the width of the widening portion 33 is too large with respect to the linear portion 32, and the heat-generating conductor 30 is used. It is possible to prevent the widening portion 33 from being visually recognized in the field of view.

It is possible to make various changes to the above-described embodiment.

In the above-described embodiment, the heating plate 10 includes the conductor-attached sheet 20 having the base film 21, but the heat generating plate 10 is formed by peeling off the base film 21 in the manufacturing process. The base film 21 may not be contained therein. In this case, the entire heat generating plate 10 can be made thinner and lighter. Further, the heat generated from the heat generating conductor 30 can be quickly transferred to the entire heat generating plate 10.

In the above-described embodiment, an example in which the heat generating plate 10 is formed in a curved surface is shown, but the present invention is not limited to this example, and the heat generating plate 10 may be formed in a flat plate shape.

The heating plate 10 may be used for the rear window, the side window, or the sunroof of the automobile 1. Further, it may be used for a transparent portion of a window or a door of a vehicle such as a railroad vehicle, an aircraft, a ship, or a spaceship other than an automobile.

Further, the heating plate 10 is used not only for vehicles but also for places that separately separate indoors and outdoors, such as buildings, stores, transparent parts of windows or doors of houses, windows or doors of buildings, refrigerators, display boxes, cupboards, and the like. It can also be used for transparent parts of windows or doors of storage or storage equipment.

Although some modifications to the above-described embodiments have been described above, it is naturally possible to apply a plurality of modifications in combination as appropriate.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

As an example and a comparative example, the heat generating plate 10 was prepared as follows. First, the heat-generating conductor 30 created in the square lattice pattern shown in FIG. 5 was combined with the base film 21 made of polyethylene terephthalate having a thickness of 50 μm to prepare a sheet 20 with a conductor. The sheet 20 with a conductor was joined to the glass substrates 11 and 12 having a thickness of 2 mm via the bonding layers 13 and 14 made of polyvinyl butyral having a thickness of 0.38 mm to form a heat generating plate 10. Depending on the substrates 11, 12, etc., the transmittance of light other than the heat-generating conductor 30 on the heat-generating plate 10 is about 80%.

In the heat generating plates 10 of Examples and Comparative Examples, samples were prepared in which the radius of curvature of the contour of the widened portion 33 of the linear conductor 31 in the heat generating conductor 30 was 10 μm, 20 μm, 60 μm, and 80 μm. Further, a sample was prepared in which the distance D between the centers of gravity of the adjacent openings 35 was 200 μm, 250 μm, 1500 μm, and 1600 μm. The line width of the linear portion 32 is 6 μm, and the thickness of the linear conductor 31 is 7 μm. The radius of curvature is the heat generating plate 10 at the maximum magnification (total 1000 times, imaging range 0.30 mm × 0.23 mm) using a digital microscope (Keyence VHX-100F) and a wide range zoom lens (Keyence VH-Z100). From the image of the light transmitted through the heat generating conductor 30 of the above, the measurement was performed by the radius measuring function attached to the above-mentioned measuring instrument. The distance between the centers of gravity was measured by imaging with transmitted illumination with an optical microscope and determining the center of gravity points of each opening 35 in the captured images.

The transparency, line visibility, and visibility of the heat generating plate 10 in the field of view through the heat generating plate 10 when exposed to light were evaluated in Examples and Comparative Examples. The evaluation results are shown in Table 1 below. The transparency was evaluated based on the transmittance being measured and the transmittance being 75% or more. In the column of "transparency" in Table 1, a circle was given to a sample having a transmittance of 75% or more, and a cross was given to a sample having a transmittance of less than 75%. The linear visibility was visually confirmed whether the linear conductor 31 was visually confirmed at a distance of 60 cm from the heating plate 10. In the column of "Line visibility" in Table 1, the sample in which the linear conductor 31 was not visually recognized was marked with a circle, and the sample in which the linear conductor 31 was visually recognized was marked with a cross. For visibility, a white LED light source is applied to the heating plate 10 from a position 3 m away, and when the light source is observed, light rays that are strong streaks and bright spots are generated in all directions, which deteriorates visibility. Was visually confirmed. In the “Visibility” column of Table 1, the samples whose visibility was not significantly reduced were marked with a circle, and the samples whose visibility was significantly reduced were marked with a cross.

Regarding the transparency, when the distance between the centers of gravity of the openings 35 is 250 μm or more, the transmittance is 75% or more, and a sufficiently clear view can be obtained even through the heat generating plate 10 having the heat generating conductor 30. Was confirmed. On the other hand, when the distance between the centers of gravity of the openings 35 was 200 μm, the field of view through the heat generating plate 10 having the heat generating conductor 30 was observed dimly. This is because if the distance between the centers of gravity is too small, the linear conductors 31 become too dense and sufficient transmittance cannot be obtained.

Regarding the line visibility, it was confirmed that each linear conductor 31 was not visible when the distance between the centers of gravity of the openings 35 was 1500 μm or less. On the other hand, when the distance between the centers of gravity of the openings 35 was 1600 μm, the linear conductor 31 was visually recognized. This is because if the distance between the centers of gravity becomes too large, the linear conductors 31 are separated from each other, making it easier for each linear conductor 31 to be visually recognized.

Regarding the visibility when the light source was applied, the radius of curvature of the contour of the widening portion 33 was 20 μm to 60 μm, and no light beam or bright spot was observed, and the visibility was good. On the other hand, when the radius of curvature was 10 μm and 80 μm, a diffraction image that deteriorated the visibility via the heating plate 10 was generated. This is because if the radius of curvature is too small, the light beam generated by the heat generating conductor 30 cannot be sufficiently blurred by the curved portion 33a of the widening portion 33, and if the radius of curvature is too large, the curved portion 33a It is considered that this is because the diffracted light generated by the above becomes conspicuous and the visibility is rather deteriorated.

Therefore, based on the examples and comparative examples in Table 1, the range of Examples 1 to 4, specifically, the radius of curvature of the contour of the widening portion 33 is 20 μm or more and 60 μm or less, and the distance between the centers of gravity is 250 μm or more and 1500 μm. In the following cases, the heat generating plate 10 has high transparency, and the linear conductor 31 of the heat generating conductor 30 is not visible even through the heat generating plate 10, and a light beam or the like is generated when light is applied. It is understood that it does not impair visibility.

Further, with respect to Example 1 in which the radius of curvature is 20 μm and the distance between the centers of gravity is 250 μm, samples having the lengths of the curved portion 33a of 18 μm and 20 μm are prepared and visually recognized while keeping the radius of curvature and the distance between the centers of gravity constant. Evaluated for sex. The evaluation results are shown in Table 2 below. In the “Visibility” column of Table 2, the samples whose visibility did not significantly decrease were marked with ◯, and the samples whose visibility hardly decreased were marked with ⊚.

It was confirmed that when the length of the curved portion 33a was 20 μm, the visibility was improved as compared with the case of 18 μm. This is because when the length of the curved portion 33a is 20 μm or more, the light beam by the widening portion 33 can be sufficiently generated, so that the light beam by the linear portion 32 can be dispersed, and the visibility is further improved. Because.

Further, with respect to Example 1 in which the radius of curvature is 20 μm and the distance between the centers of gravity is 250 μm, the ratio of the width of the widened portion 33 to the width of the linear portion 32 is 4, 5, 10 while keeping the radius of curvature and the distance between the centers of gravity constant. , 11 samples were prepared, and the line visibility and visibility were evaluated. The evaluation results are shown in Table 3 below. Regarding the line visibility, in the “Line visibility” column of Table 3, the sample in which the linear conductor 31 was visible only to the extent that it did not obstruct the field of view was marked with a circle, and was not visible to the naked eye. ◎ is attached to the sample. Regarding visibility, in the “Visibility” column of Table 3, ○ was given to the samples whose visibility did not significantly decrease, and ◎ was given to the samples whose visibility did not decrease significantly. ..

It was confirmed that when the ratio of the width of the widening portion 33 to the width of the linear portion 32 was 10 or less, the line visibility was improved as compared with the case of 11. This is because when the width ratio is larger than 10, the widening portion 33 becomes large and the intersection of the linear conductors 31 can be seen, so that line appearance occurs. Further, it was confirmed that when the ratio of the width of the widening portion 33 to the width of the linear portion 32 is 5 or more, the visibility is improved as compared with the case of 4. This is because when the ratio of the width of the widening portion 33 to the width of the linear portion 32 is less than 5, the widening portion 33 cannot be sufficiently taken and the diffraction image by the widening portion 33 is not sufficiently generated.

1 Automobile 5 Front window 7 Power supply 10 Heat generating plate 11 Board 12 Board 13 Joining layer 14 Joining layer 15 Wiring part 20 Sheet with conductor 21 Base film 25 Bus bar 30 Conductor for heat generation 31 Linear conductor 32 Linear part 33 Widening Part 33a Curved part 34 Crossing part 35 Opening part 36 Conductive metal layer 37 First dark color layer 38 Second dark color layer

Claims (6)

A heat-generating conductor that generates heat when a voltage is applied.
It has a plurality of linear conductors arranged in a pattern forming a plurality of openings, and has a plurality of linear conductors.
The linear conductor includes an intersection that intersects with another linear conductor, a linear portion that extends independently of the other linear conductor, and the line between the intersection and the linear portion. It has a widening portion that widens the width of the shape conductor,
The widened portion of the linear conductor shares a part thereof with the widened portion of another linear conductor that intersects the linear conductor.
The contour of the widened portion includes a curved portion having a radius of curvature of 15 μm or more and 60 μm or less.
The distance between the centers of gravity of the adjacent openings is 250 μm or more and 1500 μm or less.
The width of the linear portion is 2 μm or more and 15 μm or less.
The thickness of the linear conductor state, and are more 30μm or less 1 [mu] m,
A conductor for heat generation , wherein the length of the curved portion is 20 μm or more. The heat-generating conductor according to claim 1 , wherein the curved portion includes a concave curve toward the opening. The heat-generating conductor according to claim 1 or 2 , wherein the width of the widened portion is 5 times or more and 10 times or less the width of the linear portion adjacent to the widened portion. Base film and
A sheet with a conductor comprising the heat-generating conductor according to any one of claims 1 to 3 provided on the base film. A pair of boards and
A heat generating plate comprising the heat generating conductor according to any one of claims 1 to 3 or a sheet with a conductor according to claim 4 between the pair of substrates. A vehicle comprising the heating plate according to claim 5.

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