JP6976676B2 - Transparent heating plate and vehicle - Google Patents

Description

The present invention relates to a transparent heat generating plate having a pair of substrates and a heat generating conductor arranged between the pair of substrates, and a vehicle having the transparent heat generating plate.

Conventionally, a transparent heat generating plate having a pair of substrates and a heat generating conductor arranged between the pair of substrates is known. As a typical application example, the transparent heating plate is used as a heater or a defroster device. The transparent heating plate as a defroster device is used as a window glass for a front window, a rear window, or the like of a vehicle. For example, in Patent Documents 1 and 2, the transparent heating plate used as a window glass has a heating wire made of a tungsten wire or the like arranged on the entire window glass. In this transparent heating plate, the heating wire is heated by the resistance heating when the heating wire is energized. By raising the temperature of the window glass made of the transparent heat generating plate, it is possible to remove the fogging of the window glass or melt the snow and ice adhering to the window glass to secure the visibility of the occupants.

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

The transparent heat generating plate of the prior art is manufactured by heat-pressing a pair of glass plates with a joining layer and a heating wire sandwiched between them. Further, as the heating wire, a thin wire such as tungsten manufactured in another process was used, and the thin wire was arranged between the pair of glass plates. However, when observing light, for example, the illumination of an oncoming vehicle through such a transparent heating plate, a streak of light observed to trail 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.

On the other hand, as a result of repeated studies by the inventors of the present invention, the light beam was generated in the direction in which the light (for example, the illumination light of the oncoming vehicle) was diffracted by the heating wire. That is, the light beam was considered to be a phenomenon in which the diffracted light of the heating wire was visually recognized. The present invention is based on such findings of the present inventors. That is, it is an object of the present invention to make the light beam in the transparent heat generating plate inconspicuous.

The transparent heating plate in the present invention is
A pair of boards and
A pair of busbars to which voltage is applied,
The pair of bus bars are connected to each other, and at least a part thereof is provided with a heat generating conductor arranged between the pair of substrates.
The heat-generating conductor has a pattern structure formed by regularly arranging certain unit pattern structures formed by using conductive thin wires.
The normals at each position for the unit pattern structure are distributed in all directions.

In the transparent heating plate in the present invention
The unit pattern structure consists of one or more areas extending along an arc.
By translating each area and / or translating each area by 180 ° and then translating, all areas of the unit pattern structure are used to form one or more natural several semicircles. May be good.

The vehicle in the present invention comprises either the first or second transparent heating plate according to the present invention described above.

According to the present invention, the light beam on the transparent heat generating plate can be made inconspicuous.

FIG. 1 is a diagram for explaining an embodiment according to the present invention, and is a perspective view schematically showing a vehicle provided with a transparent heat generating plate. In particular, FIG. 1 schematically shows an automobile equipped with a front window made of a transparent heating plate as an example of a vehicle. FIG. 2 is a diagram showing a transparent heat generating plate from the normal direction of the plate surface. FIG. 3 is a cross-sectional view of the transparent heating plate in line III-III of FIG. FIG. 4 is a diagram for explaining the principle of light beam generation. FIG. 5 is a diagram for explaining the principle of light beam generation. FIG. 6 is a diagram for explaining the principle of light beam generation. FIG. 7 is a diagram for explaining the principle of light beam generation. FIG. 8 is a diagram for explaining the principle of light beam generation. FIG. 9 is a diagram for explaining the principle of light beam generation. FIG. 10 is a diagram for explaining the principle of light beam generation. FIG. 11 is a diagram for explaining the principle of light beam generation. FIG. 12 is a diagram for explaining the principle of light beam generation. FIG. 13 is a diagram for explaining the principle of light beam generation. FIG. 14 is a diagram for explaining the principle of light beam generation. FIG. 15 is a diagram for explaining the principle of light beam generation. FIG. 16 is a diagram showing an ideal shape of a light beam. FIG. 17 is a plan view showing the heat generating conductor from the normal direction of the sheet surface, and is a plan view showing an example of the heat generating conductor. FIG. 18 is a diagram showing a unit pattern structure of the pattern of the heat generating conductor shown in FIG. FIG. 19 is a plan view showing the heat generating conductor from the normal direction of the sheet surface, and is a plan view showing another example of the heat generating conductor. FIG. 20 is a diagram showing a unit pattern structure of the pattern of the heat generating conductor shown in FIG. FIG. 21 is a plan view showing the heat generating conductor from the normal direction of the sheet surface, and is a plan view showing another example of the heat generating conductor. FIG. 22 is a diagram showing a unit pattern structure of the pattern of the heat generating conductor shown in FIG. 21. FIG. 23 is a plan view showing the heat generating conductor from the normal direction of the sheet surface, and is a plan view showing another example of the heat generating conductor. FIG. 24 is a diagram showing a unit pattern structure of the pattern of the heat generating conductor shown in FIG. 23.

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 the present specification, the "sheet surface (plate surface, film surface)" is a target sheet when the target sheet-like (plate-like, film-like) member is viewed as a whole and in a broad sense. Refers to a surface that coincides with the plane direction of a shaped member (plate-shaped member, film-shaped member).

In addition, the terms such as "parallel", "orthogonal", and "identical" and the values of length and angle, which specify the shape and geometric conditions and their degrees, which are used in the present specification, are strictly referred to. It is interpreted to include the range where similar functions can be expected without being bound by meaning.

1 to 24 are views for explaining an embodiment of the present invention and a modification thereof. Of these, FIG. 1 is a diagram schematically showing an automobile equipped with a transparent heating plate, FIG. 2 is a view of the transparent heating plate as viewed from the normal direction of the plate surface, and FIG. 3 is a view of FIG. It is a cross-sectional view of the transparent heating plate of.

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, an example in which the front window 5 is composed of the transparent heat generating plate 10 will be described. Further, the automobile 1 has a power source 7 such as a battery.

As shown in FIGS. 2 and 3, the transparent heat generating plate 10 in the present embodiment includes a pair of substrates 11 and 12, a sheet 20 with a conductor arranged between the pair of substrates 11 and 12, and each substrate. It has a pair of bonding layers 13 and 14 for bonding 11 and 12 and the sheet 20 with a conductor. In the examples shown in FIGS. 1 and 2, the transparent heat generating plates 10 and the substrates 11 and 12 are curved, but in the other figures, the transparent heat generating plates 10 and the substrates 11 and 12 are used for easy understanding. It is shown in a flat plate.

The sheet 20 with a conductor is provided on the base film 21, the heat generating conductor 30 provided on the surface facing one of the base films 21 and including the conductive thin wire 31, and the heat generating conductor 30. It has a pair of bus bars 25 for energizing.

Further, as is well shown in FIGS. 1 and 2, the transparent heat generating plate 10 has a wiring portion 15 for energizing the heat generating conductor 30. In the illustrated example, a power source 7 such as a battery energizes the heat generating conductor 30 from the wiring portion 15 via the bus bar 25 of the sheet 20 with a conductor, 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 heated. This makes it possible to remove fogging due to dew condensation adhering to the substrates 11 and 12. 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 occupants is ensured well.

The term "transparent" of the transparent heat-generating plate means that the transparent heat-generating plate has transparency to the extent that one side of the transparent heat-generating plate can be seen through the transparent heat-generating plate. For example, it means that it has a visible light transmittance of 30% or more, more preferably 70% or more. Visible light transmittance is the average transmittance at each wavelength when measured using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, JIS K0115 compliant product) within the measurement wavelength range of 380 nm to 780 nm. Specified as a value.

Further, in the present 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 including members that can be called a plate or film, and therefore, "sheet with conductor" is "plate with conductor (board)" or "with conductor". It cannot be distinguished only by the difference in the name from the member called "film".

Hereinafter, each component of the transparent heat generating plate 10 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 the 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. However, 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, the 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 configured in the same manner, 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 a bonding layer 13 and 14, a layer made of a material having various adhesiveness or adhesiveness can be used. Further, it is preferable to use the bonding layers 13 and 14 having a 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 transparent 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 transparent heat generating plate 10, the bonding layers 13 and 14, and the base material of the sheet 20 with a conductor described later will be described. Some function may be imparted to at least one of the films 21. As an example, the functions that can be imparted to the transparent heat generating plate 10 include antireflection (AR) function, scratch resistant hard coat (HC) function, infrared shielding (reflection) function, ultraviolet shielding (reflection) function, and antireflection. The dirty function and the like can be exemplified.

Next, the sheet 20 with a conductor will be described. The sheet 20 with a conductor is provided on the base film 21, the heat generating conductor 30 provided on the surface facing one of the base films 21 and including the conductive thin wire 31, and the heat generating conductor 30. It has a pair of bus bars 25 for energizing. The sheet 20 with a conductor has substantially the same plane dimensions as the substrates 11 and 12, and may be arranged over the entire transparent heat generating plate 10, or transparent heat generation such as the front portion of the driver's seat in the example of FIG. It may be arranged only on a part of the plate 10.

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 a wavelength in the visible light wavelength band (380 nm to 780 nm). The base film 21 may be 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 annular material. 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.

Next, the heat generating conductor 30 will be described with reference to FIGS. 17, 19, 21, and 23. 17, FIG. 19, FIG. 21, and FIG. 23 are plan views of the sheet 20 with a conductor as viewed from the normal direction of the sheet surface, but the heat-generating conductors have different patterns from each other. ..

The heat generating conductor 30 has a conductive thin wire 31 arranged between the pair of bus bars 25. The conductive thin wire 31 is energized from a power source 7 such as a battery via a wiring portion 15 and a bus bar 25, and generates heat by 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 conductive thin wires 31 can be arranged in various patterns. In the example shown in FIGS. 17, 19 and 21, the heat generating conductor 30 is formed by arranging the conductive thin wires 31 in a mesh-like pattern defining a large number of openings 33. The heat generating conductor 30 includes a plurality of connecting elements 34 extending between the two branch points 32 to define the opening 33. That is, the conductive thin wire 31 of the heat generating conductor 30 is configured as a collection of a large number of connecting elements 34 forming branch points 32 at both ends.

On the other hand, as in the example shown in FIG. 23, the heat generating conductor 30 may be composed of a plurality of conductive thin wires 31 connecting the pair of bus bars 25. In the example shown in FIG. 23, the plurality of conductive thin wires 31 each extend from one bus bar 25 to the other bus bar 25 in a regular structure. The plurality of conductive thin wires 31 are arranged apart from each other in a direction non-parallel to the extending direction of the conductive thin wires 31. In particular, the plurality of conductive thin wires 31 are arranged in a direction orthogonal to the extending direction of the conductive thin wires 31. As a result, a gap 35 is formed between the two adjacent conductive thin wires 31.

An example of a specific arrangement pattern of the heat generating conductor 30 will be described later with reference to the drawings.

Materials for forming such a heat generating conductor 30 include, for example, gold, silver, copper, platinum, aluminum, chromium, molybdenum, nickel, titanium, palladium, indium, tungsten, and one of these alloys. The above can be exemplified.

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 non-covering ratio is as high as 70% or more and 90% or less. Further, the line width of the conductive thin wire 31 is about 2 μm or more and 20 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 transparent heat generating plate 10.

In the example shown in FIG. 3, the conductive thin wire 31 has a rectangular cross section as a whole. The width W of the conductive thin wire 31, that is, the width W along the plate surface of the transparent heat generating plate 10 is 2 μm or more and 20 μm or less, and the height (thickness) H, that is, the normal line to the plate surface of the transparent heat generating plate 10. The height (thickness) H along the direction is preferably 1 μm or more and 60 μm or less. According to the conductive thin wire 31 having such dimensions, the conductive thin wire 31 is sufficiently thinned, so that the heat generating conductor 30 can be effectively invisible.

Further, as shown in FIG. 3, the conductive thin wire 31 is a first dark color layer that covers the surface of the conductive metal layer 36 and the conductive metal layer 36 on the side facing the base film 21. 37. Among the surfaces of 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 conductive thin wire 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 may be deteriorated. Therefore, the first and second dark color 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 transparent heat generating plate 10 or the visibility through the transparent heat generating plate 10, the conductive thin wire 31 of the heat generating conductor 30 is set so as to have a high non-covering ratio. It is formed on the base film 21. Therefore, as shown in FIG. 3, the bonding layer 13 and the base film 21 of the sheet 20 with a conductor pass through a region between the non-covered portion of the conductive thin wire 31, that is, the adjacent conductive thin wire 31. Are in contact. Therefore, the heat generating conductor 30 is embedded in the bonding layer 13.

By the way, as described above, when observing light through a transparent heating plate containing a heating wire, for example, lighting of an oncoming vehicle, a streak of light observed to trail a tail, that is, a light beam is around the lighting. Observed. The generation of such light beams deteriorates the visibility through the transparent 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 transparent heating plate is diffracted by the heating wire. Based on the findings of the present inventors, by irregularizing the longitudinal direction of the conductive thin wire 31 forming the heat generating conductor 20, it is possible to prevent the light beam from extending in a specific direction and make the light beam inconspicuous. Can be done. However, completely irregularizing the arrangement of the conductive thin wires 31 increases the design load and is not preferable. In addition, irregularizing the arrangement of the conductive thin wires 31 may cause in-plane heat generation unevenness. Further, when visually observed in close proximity, it is easily recognized as in-plane unevenness of transmittance or reflectance. Therefore, the inventors of the present invention have conducted further diligent studies, and the orientation of the conductive thin wires 31 without significantly breaking the regularity of the arrangement of the conductive thin wires 31 and while maintaining the regularity of the arrangement of the conductive thin wires 31. It was possible to make the light beam inconspicuous extremely effectively by devising. Hereinafter, the principle of light beam generation and the method of making the light beam inconspicuous will be described with reference to FIGS. 4 to 16.

Generally, when light passes through a gap or a transmission portion of an opening formed in a structure, the light is diffracted. The diffraction image generated at this time can be visually recognized as a light beam. The shape of the diffraction image is determined by the shape of the transmissive portion of the structure, more specifically, the shape of the boundary between the transmissive portion and the shielding portion. The diffraction image becomes visible as a set of diffracted light of each order other than the 0th order. The diffraction efficiency of each order depends on the aperture ratio (non-cover ratio) D [%] of the object. The total diffraction efficiency of the 0th to infinite order diffracted light, that is, the total transmittance is D [%]. Of these, the diffraction efficiency of the 0th-order diffracted light is (D / 100) ² × 100 [%], and the total diffraction efficiency of the diffracted light other than the 0th-order diffracted light that contributes to the light beam is ((D / 100) − (D /). 100) ² ) × 100 [%]. Therefore, the total diffraction efficiency of the diffracted light other than the 0th-order diffracted light, in other words, the intensity of the diffracted image corresponding to the visibility of the light beam is the largest when the aperture ratio (non-covering ratio) D is 50%. It decreases from 50% as it becomes smaller or larger. Moreover, the intensity value of this diffraction image is symmetrical around 50%.

The non-zero-order diffraction image observed when light is incident on a certain structure is the non-zero-order diffraction image observed when light is incident on a complementary structure in which the transmissive part and the shielding part of the certain structure are inverted. The shape and intensity match the diffraction image. This is known as the Babine principle. That is, for example, a diffraction image other than the 0th order that becomes observed when light is incident on the structure 50 having the regular hexagonal transmission portion 50a (opening region) arranged in the honeycomb arrangement shown in FIG. 4 is , A structure 60 complementary to the structure of FIG. 4, that is, a structure 60 having a regular hexagonal shielding portion 60b arranged in the honeycomb arrangement shown in FIG. 5, other than the 0th order observed when light is incident on the structure 60. It becomes the same as the diffraction image of. In considering the diffraction image, it is better to see a set of simple shapes (rectangles) as shown in FIG. 5 than a shape (hexagon) having a complicated opening as shown in FIG. Further, hereinafter, the "diffraction image" refers to an image due to diffracted light other than the 0th order.

Next, the shape of the observed diffraction image is examined. The shape of the diffraction image is specified by the following method. Here, as an example, a diffraction image observed when light is incident on the pattern structure 50 of FIG. 4 in which the transmission portions 50a (opening region, uncovered region) are regularly arranged in a honeycomb arrangement will be examined. .. First, the diffraction image observed in the pattern structure 50 of FIG. 4 is the same as the diffraction image observed in the pattern structure 60 of FIG. 5 as described above. Therefore, the pattern structure 50 of FIG. 4 is replaced with the pattern structure 60 of FIG. 5 in which the shielding portions 60b are regularly arranged in a honeycomb arrangement, and the observed diffraction image is examined. In the pattern structure 60 of FIG. 5, the transmission portion 60a is a slit having a constant width surrounding the periphery of the regular hexagonal shielding portion 60b. The transmission portion 60b of the pattern structure 60 of FIG. 5 can be classified into three unit pattern elements 61, 62, 63 when divided into parallel slits. Therefore, the diffraction phenomenon that occurs when light travels through the pattern structure 60 of FIG. 5 is the diffraction phenomenon that occurs when light travels through each of the three unit pattern elements 61, 62, and 63 shown in FIGS. 6 to 8. It becomes the sum.

Of these, consider the unit pattern element 61 of FIG. Here, the unit pattern element 61 is a transmissive portion, in other words, a window element, in which innumerable slits having a length of 2 l and a line width of 2 d are arranged at a center spacing a. The unit pattern element 61 includes two components, that is, one reference element 61A having a length of 2 l and a line width of 2 d as shown in FIG. 9, and a point cloud 61B arranged innumerably at an interval a as shown in FIG. Represented by convolution. Next, assuming that the observer is sufficiently distant from the structure 50, the spatial amplitude distribution is defined as the diffraction of Fraunhofer, and the spatial amplitude distribution is Fourier transformed using the convolution theorem to obtain a diffraction image. Assuming that the wavelength of the diffracted light is λ, the Fourier transform of the reference element 61A in FIG. 9 is strongest in the central portion where the first-order bright line as shown in FIG. 11 has a line width λ / l and a length λ / d. A cardinal sine type distribution 61A1 is obtained. However, this dimension is a diffraction angle expressed in radians. Assuming that the distance of the pattern structure 50 from the observer is R, it may be considered that the primary bright line has a line width λR / l and a length λR / d on the pattern plane. In FIG. 11, since the distribution in the width direction is sufficiently small, only one cycle is shown, and the distribution in the length direction is shown only up to two cycles for simplification. In addition, the amplitude is emphasized in the second cycle. From the Fourier transform of the innumerable points arranged in FIG. 10, the distribution 61B1 of the innumerably arranged points having an interval of 2λ / (√3 × a) as shown in FIG. 12 can be obtained. The product of these distributions 61A1 and 61B1 becomes an amplitude diffraction image of the unit pattern element 61 in FIG. However, in the product of the distributions 61A1 and 61B1, the distribution 61B1 of the innumerable points arranged in FIG. 12 has an invisible fine structure and is arranged inside the amplitude distribution 61A1 in FIG. The 61A1 can be considered as a substantial amplitude diffraction image of the structure 61 of FIG.

By the same operation, the amplitude distribution 62A1 of FIG. 13 is obtained from the unit pattern element 62 of FIG. 7, and the amplitude distribution 63A1 of FIG. 14 is obtained from the unit pattern element 63 of FIG. The superposition of the respective amplitude distributions 61A1, 62A1, 63A1 is the amplitude diffraction image of the original pattern structure 60, and the intensity distribution of the diffraction image in which the square is observed. That is, from the pattern structure 50 of FIG. 4, the intensity distribution 60A1 of FIG. 15, which is an intensity distribution obtained by superimposing and squared the amplitude distributions 61A1, 62A1, 63A1 of FIGS. 11, 13, and 14, is observed as a diffraction image. To.

As described above, the diffraction image observed from the pattern structure 50 illustrated in FIG. 4 is three streaky lights extending in three different directions as shown in the intensity distribution 60A1 in FIG. This streaky light is observed as a light beam. And, such a light beam has a strong influence on the visibility through the transparent heat generating plate 10.

The diffraction image having a small influence on the visibility through the transparent heat generating plate 10 is a streak-like light, that is, an image containing no light beam. As an example of such a diffraction image, it is conceivable that the diffraction efficiency of the multi-order diffracted light is low, or that the light beam extends in all directions and the individual light beam cannot be identified. The latter is preferably observed as a circular diffraction image 70 as shown in FIG.

The amplitude distribution 61A1 shown in FIG. 11 produced by the unit pattern element 61 shown in FIG. 6, the amplitude distribution 62A1 shown in FIG. 13 produced by the unit pattern element 62 shown in FIG. 7, and FIG. 8 are shown. As can be seen from the amplitude distribution 63A1 shown in FIG. 14 produced by the unit pattern element 63, the diffraction image produced by the linear structure having the longitudinal direction is in the direction orthogonal to the longitudinal direction of the structure. It extends and becomes a light beam. Therefore, in order for the light beams to extend in all directions and, as a result, a large number of light rays overlap each other and be visually recognized in a circular shape, the normals orthogonal to the longitudinal direction of each structural element forming one structure are omnidirectional. It suffices if it is distributed over. As such a structure, for example, a structure formed by a Voronoi pattern can be considered. In addition, when the structure has regularity and the normals orthogonal to the longitudinal direction of each component forming the unit pattern structure forming one rule are distributed in all directions, it is caused by the unit pattern structure. Not only the light beam generated as a result, but also the light beam generated due to the entire pattern structure can be grasped as a circular bright part.

As such a structure, here one unit pattern structure consists of one or more areas extending along an arc, translating each area and / or translating each area 180 ° and then translating. Thus, we consider a pattern structure in which one or more natural several semicircles are formed using all the components that form one unit pattern structure. There are two directions opposite to each other in the normal direction of the area. Therefore, if the set of areas forms a semicircle, the normal direction extends in all directions. Moreover, even if each area is rotated by 180 °, the distribution in the normal direction does not change. Therefore, in order for the normals of each area to be distributed in all directions, each area may be partially rotated by 180 ° and then moved in parallel to form a semicircle.

An example of the heat generating conductor 30 having the above-mentioned pattern structure will be described below with reference to FIGS. 17 to 24.

(Example of first pattern structure)
First, as a first pattern structure example, the pattern structure shown in FIGS. 17 and 18 will be described. The pattern structure of the heat generating conductor 30 arranged as shown in FIG. 17 by the conductive thin wire 31 is formed by arranging a large number of unit pattern structures shown in FIG. 18 in a plane.

The unit pattern structure of FIG. 18 is formed by connecting areas 31a1, 31b1, 31c1, and 31d1 counterclockwise in this order along four arcs having the same radius cut out at a central angle of 90 °. .. Expressed using the angle made counterclockwise with respect to the reference axis extending to the right in the figure, the area 31a1 has a central angle of 0 ° to 45 ° and a range of 315 ° to 360 ° in one circle. It forms an arc located at. The area 31b1 forms an arc located in the range of the central angle of 225 ° to 315 ° in one circle. The area 31c1 forms an arc located in the range of the central angle of 135 ° to 225 ° in one circle. The area 34d1 forms an arc located in the range of the central angle of 45 ° to 135 ° in one circle. The normals at each position in all the areas forming this unit pattern structure are distributed over 360 °. In other words, the normals at each position for the unit pattern structure are distributed in all directions. Further, when the positions of the areas 31b1 and 31d1 are exchanged by translation, the areas 31a1, 31b1, 31c1, and 31d1 form two semicircles. In other words, the unit pattern structure consists of one area extending along an arc, and by translating each area and / or translating each area by 180 ° and then translating, all of the unit pattern structure. Two semicircles are formed using the area of.

The pattern structure of FIG. 17 is formed by regularly laying the unit pattern structure of FIG. 18 described above without gaps. Therefore, in the transparent heat generating plate 10 using the heat generating conductor 30 having the pattern structure of FIG. 17, the light beam in each direction is similarly formed and the light beam is generated in all directions. Therefore, a large number of light beams overlap each other and are visually recognized in a circular shape.

(Second pattern structure example)
Next, as a second pattern structure example, the pattern structure shown in FIGS. 19 and 20 will be described. The pattern structure of the heat generating conductor 30 arranged as shown in FIG. 19 by the conductive thin wire 31 is formed by arranging a large number of unit pattern structures shown in FIG. 20 in a plane.

The unit pattern structure of FIG. 20 is formed by connecting areas 31a2, 31b2, 31c2 at one point counterclockwise in this order along three arcs having the same radius cut out at a central angle of 60 °. .. Expressed using the angle made counterclockwise with respect to the reference axis extending to the right in the figure, the area 31a2 has a central angle of 0 ° to 30 ° and a range of 330 ° to 360 ° in one circle. It forms an arc located at. The area 31b2 forms an arc located in the range of the central angle of 90 ° to 150 ° in one circle. The area 31c2 forms an arc located in the range of the central angle of 210 ° to 270 ° in one circle. The normals at each position in all the areas forming this unit pattern structure are distributed over 360 °. In other words, the normals at each position for the unit pattern structure are distributed in all directions. Further, by rotating the area 31a2 by 180 ° and then translating it, the areas 31a2, 31b2, 31c2 form one semicircle. In other words, the unit pattern structure consists of one area extending along an arc, and by translating each area and / or translating each area by 180 ° and then translating, all of the unit pattern structure. Two semicircles are formed using the area of.

The pattern structure of FIG. 19 is formed by regularly laying the unit pattern structure of FIG. 20 described above without gaps. Therefore, in the transparent heat generating plate 10 using the heat generating conductor 30 having the pattern structure of FIG. 19, the light beam in each direction is similarly formed and the light beam is generated in all directions. Therefore, a large number of light beams overlap each other and are visually recognized in a circular shape. Further, since the pattern structure of FIG. 19 can have a wider opening 33 than the pattern structure of FIG. 17, it can further contribute to the invisibility of the conductive thin wire 31.

(Third pattern structure example)
Next, as a third pattern structure example, the pattern structure shown in FIGS. 21 and 22 will be described. The pattern structure of the heat generating conductor 30 arranged as shown in FIG. 21 by the conductive thin wire 31 is formed by arranging a large number of unit pattern structures shown in FIG. 22 in a plane.

In the unit pattern structure of FIG. 22, the areas 31a3, 31b3, 31c3, 31d3, 31e3, 31f3, 31g3, 31h3 extending along eight arcs having the same radius cut at a central angle of 90 ° are counterclockwise in this order. It is formed by being connected around. Expressed using the angles formed counterclockwise with respect to the reference axis extending to the right in the figure, the areas 31a3 and 31d3 have the central angles of 0 ° to 45 ° and 315 ° in one circle, respectively. It forms an arc located in the range of 360 °. The areas 31b3 and 31g3 each form an arc located in the range of the central angle of 225 ° to 315 ° in one circle. The areas 31c3 and 31f3 each form an arc located in the range of a central angle of 45 ° to 135 ° in one circle. The areas 31e3 and 31h3 each form an arc located in the range of a central angle of 135 ° to 225 ° in one circle. In this unit pattern structure, the normals at each position in all areas are distributed over 360 °. In other words, the normals at each position for the unit pattern structure are distributed in all directions. Further, one circle is formed by translating the areas 31a3, 31b3, 31c3, 31d3, and one circle is formed by translating the areas 31e3, 31f3, 31g3, 31h3. That is, two circles of the same size are formed using all the areas forming the unit pattern structure of FIG. In other words, the unit pattern structure consists of one or more areas extending along an arc, and by translating each area and / or by translating each area 180 ° and then translating. The area is used to form four semicircles.

The pattern structure of FIG. 21 is formed by regularly laying out the unit pattern structure of FIG. 22 described above without any gaps. Therefore, in the transparent heat generating plate 10 using the heat generating conductor 30 having the pattern structure of FIG. 21, the light beam in each direction is similarly formed and the light beam is generated in all directions. Therefore, a large number of light beams overlap each other and are visually recognized in a circular shape. Further, since the pattern structure of FIG. 21 can have a wider opening 33 than the pattern structure of FIG. 19, it can further contribute to the invisibility of the conductive thin wire 31.

(Fourth pattern structure example)
Finally, as a fourth pattern structure example, the pattern structure shown in FIGS. 23 and 24 will be described. The pattern structure of the heat generating conductor 30 arranged as shown in FIG. 23 by the conductive thin wire 31 is formed by continuously connecting the unit pattern structures shown in FIG. 24.

The unit pattern structure of FIG. 24 is formed by connecting areas 31a4 and 31b4 extending along two arcs having the same radius cut at a central angle of 180 ° in opposite directions to each other. In this unit pattern structure, the normals at each position in all areas are distributed over 360 °. In other words, the normals at each position for the unit pattern structure are distributed in all directions. Further, since the areas 31a4 and 31b4 are semicircles, respectively, two semicircles of the same size are formed by using all the areas of the unit pattern structure. In other words, the unit pattern structure consists of one or more areas extending along an arc, by translating each area and / or by translating each area 180 ° and then translating. Two semicircles are formed using all areas of the structure.

The heat-generating conductor 30 of FIG. 23 is formed by a regular pattern based only on the unit pattern structure of FIG. 24 as described above. Therefore, in the transparent heat generating plate 10 made of the heat generating conductor 30 having the pattern structure of FIG. 23, the light beam in each direction is similarly formed and the light beam is generated in all directions. Therefore, a large number of light beams overlap each other and are visually recognized in a circular shape.

Although the pattern structure examples in which the first to fourth heat generating conductors 30 are arranged have been shown above, these are merely examples and do not limit the embodiment.

As described above, in the transparent heat generating plate 10 of the present embodiment, a pair of substrates 11 and 12, a pair of bus bars 25 to which a voltage is applied, and a pair of bus bars 25 are connected, and at least a part thereof is a pair of substrates 11. , 12 is provided with a heat generating conductor 30 and the heat generating conductor 30 is formed by regularly arranging a constant unit pattern structure formed by using the conductive thin wire 31. It has a pattern structure 31, and the normals at each position for the unit pattern structure are distributed in all directions. According to such a transparent heat generating plate 10, the longitudinal direction of the generated light beam can be distributed over 360 °. Therefore, the light beams extend in all directions, and as a result, a large number of light rays overlap each other and are visually recognized in a circular shape without distinguishing each light beam from the other light beams. Therefore, it is possible to reduce the influence of the light beam on the visibility, and it is possible to secure a good field of view even through the transparent heat generating plate 10. Further, since a certain pattern structure is regularly arranged, uneven heat generation is less likely to occur in the transparent heat generating plate 10. Therefore, since the transparent heat generating plate 10 can generate heat uniformly, it is possible to reliably exert the function without removing the cloudiness of a part or not melting the snow. In addition, the regular arrangement of the conductive thin wires 31 has a small design load and is easy to manufacture. Therefore, the manufacturing cost can be reduced.

Further, in the transparent heating plate 10 of the present embodiment, the unit pattern structure consists of one or more areas extending along an arc, and after translating each area and / or rotating each area by 180 °. By translating, one or more natural several semicircles are formed using all areas of the unit pattern structure. According to such a transparent heat generating plate 10, the light beam extends in all directions, and the intensity of the light beam in each direction can be made uniform. Therefore, it is possible to effectively prevent a large number of light beams from overlapping each other and visually recognizing in a circular shape, and each light beam being distinguished from other light beams and being recognized. Therefore, the influence of the light beam on the visibility can be reduced, and a better view can be secured through the transparent heat generating plate 10.

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

The transparent 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 windows of vehicles such as railways, aircraft, ships, and spacecraft other than automobiles.

Further, the transparent heat generating plate 10 can be used not only for a vehicle but also for a place that separates indoors and outdoors, for example, a window of a building, a store, or a house.

1 Automobile 5 Front window 7 Power supply 10 Transparent heating 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 Conductive wire 32 Branch point 33 Opening 34 Connection element 35 Gap 36 Conductive metal layer 37 First dark color layer 38 Second dark color layer

Claims (3)

A pair of boards and
A pair of busbars to which voltage is applied,
The pair of bus bars are connected to each other, and at least a part thereof is provided with a heat generating conductor arranged between the pair of substrates.
The heat-generating conductor has a pattern structure formed by regularly arranging certain unit pattern structures formed by using conductive thin wires.
The heating conductor comprises a plurality of connecting elements extending between the two bifurcation points and defining an opening.
The unit pattern structure is formed by connecting eight arcs having the same radius cut at a central angle of 90 ° so as to form one said opening.
The normals at each position for the unit pattern structure are distributed in all directions.
The heat-generating conductor is a transparent heat-generating plate connected to the pair of bus bars in a part of the unit pattern structure. The unit pattern structure consists of one or more areas extending along an arc.
By translating each area and / or rotating each area 180 ° and then translating, all areas of the unit pattern structure are used to form one or more natural several semicircles. , The transparent heating plate according to claim 1. A vehicle provided with the transparent heating plate according to claim 1 or 2.

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