Film heater

Abstract

To provide a film heater suppressing local heat generation of a transparent conductive film.SOLUTION: A film heater 10 includes: a transparent conductive film 30 including an upper base part 301 extending in one direction, a lower base part 302 having a length in the one direction greater than an upper base part length Lu, a first oblique side part 311 that is connected to the upper base part and extends in a direction intersecting the one direction, and a second oblique side part 312 that is connected to the side opposite the first oblique side part in the upper base part, and extends in a direction intersecting the one direction; a first electrode 41 having a first connection part 411 connected to the first oblique side part; and a second electrode 42 having a second connection part 412 connected to the second oblique side part. The transparent conductive film transmits electromagnetic waves, and generates heat when a current flows in the one direction therethrough between the first connection part and the second connection part. The upper base part length Lu is greater than shortest distances Lmin1, Lmin2 from the lower base part to the first connection part and to the second connection part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a film heater.

Background Art

[0002] Conventionally, as described in Patent Document 1, a film heater having a substantially hexagonal or substantially trapezoidal transparent conductive film, a first connection portion connected to the hypotenuse portion of the transparent conductive film, and a second connection portion connected to the bottom portion of the transparent conductive film is known. In this film heater, an electric current flows through the transparent conductive film between the first connection portion and the second connection portion, and the transparent conductive film generates heat.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when the voltage applied to the transparent conductive film and the electrical resistance per unit area of the transparent conductive film are fixed, the power density, which is the power per unit area of the transparent conductive film, increases as the distance between the first connection portion and the second connection portion decreases. Further, in the film heater described in Patent Document 1, the first connection portion is connected to the hypotenuse portion of the transparent conductive film, and the second connection portion is connected to the bottom portion of the transparent conductive film. Therefore, the distance between the first connection portion and the second connection portion on the bottom portion side is smaller than the distance between the first connection portion and the second connection portion on the upper portion side. Thus, in this case, in the film heater described in Patent Document 1, the power density between the first connection portion and the second connection portion on the bottom portion side is higher than the power density between the first connection portion and the second connection portion on the upper portion side. Therefore, local heating is likely to occur in the transparent conductive film between the first connection portion and the second connection portion on the bottom portion side.

[0005] The purpose of this disclosure is to provide a film heater that suppresses localized heat generation in a transparent conductive film. [Means for solving the problem]

[0006] The invention described in claim 1 is a film heater comprising: a first bottom portion (301) extending in one direction; a second bottom portion (302) facing the first bottom portion in a direction perpendicular to one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in one direction greater than the length (Lu) of the first bottom portion in one direction; a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting one direction; and a second slanted edge portion connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting one direction. The device comprises a transparent conductive film (30) having (312), a first electrode (41) having a first connection part (411) connected to the first hypotenuse, and a second electrode (42) having a second connection part (412) connected to the second hypotenuse, wherein the transparent conductive film transmits electromagnetic waves and generates heat when a current flows in one direction within the transparent conductive film between the first and second connection parts, and the length (Lu) of the first bottom in one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connection parts. Therefore, the electrical resistance of the first bottom-side end (461) of the first connection is greater than the electrical resistance of the second bottom-side end (462) of the first connection. It's a film heater. Furthermore, the invention described in claim 2 is a film heater comprising a transparent conductive film (30) having a first bottom portion (301) extending in one direction, a second bottom portion (302) facing the first bottom portion in a direction perpendicular to one direction and the thickness direction (DT) of the film heater and having a length (Ld) in one direction greater than the length (Lu) of the first bottom portion in one direction, a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting one direction, and a second slanted edge portion (312) connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting one direction, and a first contact connected to the first slanted edge portion The film heater comprises a first electrode (41) having a connecting portion (411) and a second electrode (42) having a second connecting portion (412) connected to a second hypotenuse, wherein the transparent conductive film transmits electromagnetic waves and generates heat when a current flows in one direction within the transparent conductive film between the first and second connecting portions, the length (Lu) of the first bottom in one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connecting portions, and the electrical resistance of the end portion (463) of the second connecting portion on the first bottom side is greater than the electrical resistance of the end portion (464) of the second connecting portion on the second bottom side. Furthermore, the invention described in claim 3 is a film heater comprising: a first bottom portion (301) extending in one direction; a second bottom portion (302) facing the first bottom portion in a direction perpendicular to one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in one direction greater than the length (Lu) of the first bottom portion in one direction; a first slanted side portion (311) connected to the first bottom portion and extending in a direction intersecting one direction; and a portion of the first bottom portion connected to the side opposite to the first slanted side portion. The device comprises a transparent conductive film (30) having a second hypotenuse (312) extending in a direction intersecting one direction, a first electrode (41) having a first connection (411) connected to the first hypotenuse, and a second electrode (42) having a second connection (412) connected to the second hypotenuse, wherein the transparent conductive film transmits electromagnetic waves and generates heat when a current flows in one direction within the transparent conductive film between the first and second connection portions, and the length (Lu) of the first bottom in one direction is equal to the length of the second bottom The distance from the section to the first and second connection sections is greater than the shortest distance (Lmin1, Lmin2), and the first connection section has a plurality of corrugated sections (441) that are connected to each other and arranged in a line, and the corrugated sections have a first extension (451) that extends in the direction in which the surface of the transparent conductive film extends, a second extension (452) that is connected to the first extension and extends in a direction intersecting the direction in which the first extension extends, and a second extension that is connected to the second extension and intersecting the direction in which the second extension extends The film heater includes a third extension (453) extending in a certain direction, and a fourth extension (454) connected to the third extension and extending in a direction intersecting the direction in which the third extension extends, thereby facing the direction in which the second and first extensions extend. The end of the fourth extension opposite to the third extension (4540) is connected to the end of the first extension in the adjacent corrugated section opposite to the second extension (4510), so that adjacent corrugated sections are connected and lined up.

[0007] As a result, the length of the first bottom is relatively large, which prevents the distance between the first and second connection points from becoming relatively small. Therefore, the localized increase in power density within the transparent conductive film between the first and second connection points is suppressed. Consequently, localized heat generation in the transparent conductive film is suppressed.

[0008] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0009] [Figure 1] A diagram showing the configuration of a vehicle in which the film heater of the first embodiment is used. [Figure 2] Enlarged view from the arrow pointing to II in Figure 1. [Figure 3] Front view of the film heater. [Figure 4] Figure 3 shows an enlarged cross-sectional view of the line IV-IV. [Figure 5] Enlarged view of section V in Figure 3. [Figure 6] Enlarged view of section VI in Figure 5. [Figure 7] Enlarged view of section VII in Figure 5. [Figure 8] Enlarged view of section VIII in Figure 5. [Figure 9] Enlarged view of section IX in Figure 5. [Figure 10] Front view of the comparative example film heater. [Figure 11] Front view of the film heater according to the second embodiment. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be denoted by the same reference numeral, and their descriptions will be omitted.

[0011] (First Embodiment) In this embodiment of the film heater, localized heat generation of the transparent conductive film is suppressed. Specifically, the film heater is used, for example, in a vehicle. First, let's describe this vehicle.

[0012] As shown in Figure 1, the vehicle 1 is equipped with a windshield 3, a camera 5, and a film heater 10.

[0013] The windshield 3 corresponds to a transparent body that transmits electromagnetic waves such as radio waves and light, and secures the field of view in front of the driver of the vehicle 1. Further, as shown in FIG. 2, the windshield 3 has a first shielding portion 7 and a second shielding portion 9. The first shielding portion 7 and the second shielding portion 9 are formed of black ceramics or the like to shield electromagnetic waves. Further, the first shielding portion 7 and the second shielding portion 9 are formed on the vehicle interior side of the vehicle 1 in the windshield 3. In FIG. 2, in order to make the locations of the first shielding portion 7 and the second shielding portion 9 easy to understand, the first shielding portion 7 and the second shielding portion 9 are shown as dot patterns. Here, the first shielding portion 7 and the second shielding portion 9 are formed on the vehicle interior side of the vehicle 1 in the windshield 3, but are not limited thereto, and may be formed on the vehicle exterior side of the vehicle 1 in the windshield 3.

[0014] Returning to FIG. 1, the camera 5 is disposed above the vehicle 1 in the vehicle interior of the vehicle 1. Further, the camera 5 images the front of the vehicle 1.

[0015] The film heater 10 is attached along the inclination of the windshield 3 on the vehicle interior side of the windshield 3 and faces the camera 5 in the vehicle longitudinal direction. Further, the film heater 10 generates heat to defrost, melt snow, and prevent fogging of the portion of the windshield 3 that faces the camera 5 in the vehicle longitudinal direction. Thereby, the field of view of the camera 5 becomes clear.

[0016] As described above, the vehicle 1 is configured. Next, details of the film heater 10 will be described.

[0017] As shown in FIGS. 3 to 9, the film heater 10 includes an adhesive layer 15, a first transparent insulator 21, a second transparent insulator 22, a transparent conductive film 30, a first electrode 41, and a second electrode 42. Here, in order to make the description of the configuration of the film heater 10 easy to understand, the upper side of the paper surface of FIG. 3 is simply described as the upper side. The lower side of the paper surface of FIG. 3 is simply described as the lower side. The left side of the paper surface of FIG. 3 is simply described as the left side. The right side of the paper surface of FIG. 3 is simply described as the right side.

[0018] The adhesive layer 15 is formed of, for example, OCA. Furthermore, as shown in Figure 4, the adhesive layer 15 is attached to the passenger compartment side of the windshield 3. OCA stands for Optically Clear Adhesive.

[0019] The first transparent insulator 21 and the second transparent insulator 22 are made of a resin such as polycarbonate and therefore have electrical insulating properties. In addition, the first transparent insulator 21 is connected to the side of the adhesive layer 15 opposite to the windshield 3.

[0020] The transparent conductive film 30 is formed of ITO or carbon nanotubes, and therefore transmits electromagnetic waves while being conductive. ITO is an abbreviation for indium tin oxide.

[0021] Furthermore, the transparent conductive film 30 is covered by the first transparent insulator 21 and the second transparent insulator 22. The transparent conductive film 30 is also formed in a planar shape. Furthermore, the transparent conductive film 30 is formed in a hexagonal shape. In addition, as shown in Figures 3 and 5, the transparent conductive film 30 has an upper bottom portion 301, a lower bottom portion 302, a first slanted side portion 311, a second slanted side portion 312, a first intermediate portion 321, and a second intermediate portion 322.

[0022] The upper bottom portion 301 corresponds to the first bottom portion and extends in one direction, in this case, the left-right direction. The lower bottom portion 302 corresponds to the second bottom portion and extends in one direction, in this case, the left-right direction. Furthermore, the lower bottom portion 302 faces in a direction perpendicular to both one direction and the thickness direction DT of the transparent conductive film 30, in this case, the up-down direction. The thickness direction DT of the transparent conductive film 30 corresponds to the thickness direction DT of the film heater 10.

[0023] Here, the length of the upper base 301 in the left-right direction is denoted as the upper base length Lu. The length of the lower base 302 in the left-right direction is denoted as the lower base length Ld. The lower base length Ld is greater than the upper base length Lu, i.e., Ld > Lu.

[0024] The first hypotenuse 311 is connected to the upper base 301. Furthermore, the first hypotenuse 311 extends in a direction intersecting one direction from the boundary with the upper base 301, in this case, in the lower left direction.

[0025] The second hypotenuse 312 is connected to the upper base 301 on the side opposite to the first hypotenuse 311. Furthermore, the second hypotenuse 312 extends in a direction intersecting one direction from the boundary with the upper base 301, in this case, downward to the right.

[0026] The first intermediate section 321 is connected to the side of the first hypotenuse section 311 opposite to the upper base section 301. Furthermore, the first intermediate section 321 extends in a direction intersecting the direction in which the first hypotenuse section 311 extends from its boundary with the first hypotenuse section 311, in this case, downward. The first intermediate section 321 is also connected to the lower base section 302.

[0027] The second intermediate section 322 is connected to the side of the second hypotenuse section 312 opposite to the upper base section 301. Furthermore, the second intermediate section 322 extends in a direction intersecting the direction in which the second hypotenuse section 312 extends from its boundary with the second hypotenuse section 312, in this case, downward. In addition, the second intermediate section 322 is connected to the side of the lower base section 302 opposite to the first intermediate section 321.

[0028] The first electrode 41 is made of a metal such as gold, platinum, silver, copper, or aluminum. Furthermore, the first electrode 41 is the positive electrode in this case. The first electrode 41 also has a first connecting portion 411, a first lead portion 421, and a first terminal portion 431.

[0029] The first connection portion 411 is connected to the boundary between the upper base portion 301 and the first hypotenuse portion 311, and to the first hypotenuse portion 311. Furthermore, the first connection portion 411 is covered by the first transparent insulator 21 and the second transparent insulator 22. In addition, the first intermediate portion 321 makes the first shortest distance Lmin1 from the first connection portion 411 to the lower base portion 302 greater than zero. Furthermore, the first shortest distance Lmin1 is less than the upper base length Lu, i.e., Lmin1 <Luとされている。

[0030] Furthermore, as shown in Figure 4, the first connecting portion 411 overlaps with the projected first shielding portion 7 when the first shielding portion 7 is projected in the thickness direction DT. In Figure 4, the first shielding portion 7 is shown with a dot pattern to make its location easier to understand.

[0031] Furthermore, the first connecting portion 411 has a plurality of first corrugated portions 441, as shown in Figures 6 and 7. The first corrugated portions 441 are connected to each other and arranged in a row. The first corrugated portions 441 also include a first extension portion 451, a second extension portion 452, a third extension portion 453, and a fourth extension portion 454.

[0032] The first extension 451 extends in the direction in which the surface of the transparent conductive film 30 extends, in this case, from the upper bottom portion 301 toward the lower left. The second extension 452 is connected to the first extension 451. Furthermore, the second extension 452 extends from the boundary with the first extension 451 in a direction that intersects with the direction in which the first extension 451 extends, in this case toward the upper left. The third extension 453 is connected to the second extension 452. Furthermore, the third extension 453 extends from the boundary with the second extension 452 in a direction that intersects with the direction in which the second extension 452 extends, in this case toward the lower left. The fourth extension 454 is connected to the third extension 453. Furthermore, the fourth extension 454 extends from the boundary with the third extension 453 in a direction that intersects with the direction in which the third extension 453 extends, in this case toward the lower right. As a result, the second extension 452 faces the direction in which the fourth extension 454 and the first extension 451 extend, in this case, the direction to the lower left. Note that the first extension 451, the second extension 452, the third extension 453, and the fourth extension 454 extend in a straight line, but are not limited to this. The first extension 451, the second extension 452, the third extension 453, and the fourth extension 454 may also extend in a curved shape.

[0033] Furthermore, the end 4540 of the fourth extension 454 opposite to the third extension 453 is connected to the end 4510 of the adjacent first wavy section 441 opposite to the second extension 452 of the first extension 451. As a result, adjacent first wavy sections 441 are connected and lined up side by side. Therefore, the first connecting section 411 has a meandering shape.

[0034] Furthermore, as shown in Figures 3, 5, and 6, the first wavy portion 441 on the uppermost bottom 301 side is defined as the first end portion 461. Also, as shown in Figures 3, 5, and 7, the first wavy portion 441 on the lowermost bottom 302 side is defined as the second end portion 462. For example, the conductivity of the first end portion 461 is smaller than that of the second end portion 462. Furthermore, the length of the current path through the first end portion 461 is larger than the length of the current path through the second end portion 462. Also, the cross-sectional area of ​​the first end portion 461 when cut in a direction perpendicular to the direction of the current flowing through it is smaller than the cross-sectional area of ​​the second end portion 462 when cut in a direction perpendicular to the direction of the current flowing through it. As a result, the electrical resistance of the first end portion 461 is greater than that of the second end portion 462.

[0035] As shown in Figures 3 and 5, the first lead portion 421 is connected to the lower base portion 302 and the first intermediate portion 321. Furthermore, the first lead portion 421 is connected to the lower base portion 302 side of the first connecting portion 411. Note that the first lead portion 421 is not limited to being connected to the lower base portion 302, the first intermediate portion 321, and the lower base portion 302 side of the first connecting portion 411, but may also be connected to the upper base portion 301 side of the first connecting portion 411.

[0036] Further, the first lead portion 421 is covered by the first transparent insulator 21 and the second transparent insulator 22. Further, as shown in FIG. 4, when the first shielding portion 7 is projected in the thickness direction DT, the first lead portion 421 overlaps with the projected first shielding portion 7. Returning to FIGS. 3 and 5, the first lead portion 421 extends together with the second lead portion 422 described later so as to surround the transparent conductive film 30, the first connection portion 411, and the second connection portion 412. Thereby, the first lead portion 421 faces the first connection portion 411 in the left - right direction and faces the upper bottom portion 301 in the up - down direction.

[0037] As shown in FIG. 3, the first terminal portion 431 is connected to the first lead portion 421. Also, the first terminal portion 431 is connected to a power source not shown.

[0038] Here, the length from the first terminal portion 431 to the upper bottom portion 301 in the up - down direction, which is a direction orthogonal to the one - direction and the thickness direction DT, is defined as the first lead length L1. And the first lead length L1 is larger than the upper bottom length Lu, that is, L1>Lu.

[0039] The second electrode 42 is formed of a metal such as gold, platinum, silver, copper, or aluminum. Further, the second electrode 42 is a negative electrode here. Also, the second electrode 42 has a second connection portion 412, a second lead portion 422, and a second terminal portion 432.

[0040] The second connection portion 412 is connected to the boundary portion between the upper bottom portion 301 and the second inclined side portion 312 and the second inclined side portion 312. Further, the second connection portion 412 is covered by the first transparent insulator 21 and the second transparent insulator 22. Here, the second shortest distance Lmin2 from the second connection portion 412 to the lower bottom portion 302 by the second intermediate portion 322 is larger than zero. Further, the second shortest distance Lmin2 is the same as the first shortest distance Lmin1 and is smaller than the upper bottom length Lu, that is, Lmin1 = Lmin2<Lu. Note that the second shortest distance Lmin2 is not limited to being the same as the first shortest distance Lmin1 and may be different from the first shortest distance Lmin1.

[0041] Furthermore, as shown in Figure 4, when the second shielding portion 9 is projected in the thickness direction DT, the second connecting portion 412 overlaps with the projected second shielding portion 9. In Figure 4, the second shielding portion 9 is shown with a dot pattern to make its location easier to understand.

[0042] Furthermore, the second connecting portion 412 has a plurality of second corrugated portions 442, as shown in Figures 8 and 9. The second corrugated portions 442 are connected to each other and arranged in a row. The second corrugated portions 442 also include a fifth extension portion 455, a sixth extension portion 456, a seventh extension portion 457, and an eighth extension portion 458.

[0043] The fifth extension 455 extends in the direction in which the surface of the transparent conductive film 30 extends, in this case, from the upper bottom portion 301 toward the lower right. The sixth extension 456 is connected to the fifth extension 455. Furthermore, the sixth extension 456 extends from the boundary with the fifth extension 455 in a direction that intersects with the direction in which the fifth extension 455 extends, in this case toward the upper right. The seventh extension 457 is connected to the sixth extension 456. Furthermore, the seventh extension 457 extends from the boundary with the sixth extension 456 in a direction that intersects with the direction in which the sixth extension 456 extends, in this case toward the lower right. The eighth extension 458 is connected to the seventh extension 457. Furthermore, the eighth extension 458 extends from the boundary with the seventh extension 457 in a direction that intersects with the direction in which the seventh extension 457 extends, in this case toward the lower left. As a result, the sixth extension 456 faces the direction in which the eighth extension 458 and the fifth extension 455 extend, in this case, the direction to the lower right. Note that the fifth extension 455, the sixth extension 456, the seventh extension 457, and the eighth extension 458 extend in a straight line, but are not limited to this. The fifth extension 455, the sixth extension 456, the seventh extension 457, and the eighth extension 458 may also extend in a curved shape.

[0044] Furthermore, the end 4580 of the eighth extension 458 opposite to the seventh extension 457 is connected to the end 4550 of the fifth extension 455 of the adjacent second wavy section 442 opposite to the sixth extension 456. As a result, adjacent second wavy sections 442 are connected and lined up side by side. Therefore, the second connecting section 412 has a meandering shape.

[0045] Furthermore, as shown in Figures 3, 5, and 8, the second wavy portion 442 on the uppermost bottom 301 side is defined as the third end portion 463. Also, as shown in Figures 3, 5, and 9, the second wavy portion 442 on the lowermost bottom 302 side is defined as the fourth end portion 464. For example, the conductivity of the third end portion 463 is smaller than that of the fourth end portion 464. Furthermore, the length of the current path through the third end portion 463 is larger than the length of the current path through the fourth end portion 464. Also, the cross-sectional area of ​​the third end portion 463 when cut in a direction perpendicular to the direction of the current flowing through the third end portion 463 is smaller than the cross-sectional area of ​​the fourth end portion 464 when cut in a direction perpendicular to the direction of the current flowing through the fourth end portion 464. As a result, the electrical resistance of the third end portion 463 is greater than that of the fourth end portion 464.

[0046] As shown in Figures 3 and 5, the second lead portion 422 is connected to the lower base portion 302 and the second intermediate portion 322. Furthermore, the second lead portion 422 is connected to the lower base portion 302 side of the second connecting portion 412. Note that the second lead portion 422 is not limited to being connected to the lower base portion 302, the second intermediate portion 322, and the lower base portion 302 side of the second connecting portion 412, but may also be connected to the upper base portion 301 side of the second connecting portion 412.

[0047] Furthermore, the second lead portion 422 is covered by the first transparent insulator 21 and the second transparent insulator 22. In addition, as shown in Figure 4, when the second shielding portion 9 is projected in the thickness direction DT, the second lead portion 422 overlaps with the projected second shielding portion 9. Returning to Figures 3 and 5, the second lead portion 422 extends together with the first lead portion 421 so as to surround the transparent conductive film 30, the first connection portion 411, and the second connection portion 412. As a result, the second lead portion 422 faces the second connection portion 412 in the left-right direction.

[0048] As shown in Figure 3, the second terminal section 432 is connected to the second lead section 422. The second terminal section 432 is also connected to a power supply (not shown).

[0049] Here, the length from the second terminal portion 432 to the upper base portion 301 in the direction perpendicular to the unidirectional and thickness direction DT, in this case the vertical direction, is defined as the second lead length L2. The second lead length L2 is set to be the same as the first lead length L1 and greater than the upper base length Lu, i.e., L1 = L2 > Lu. However, the second lead length L2 is not limited to being the same as the first lead length L1 and may be different from the first lead length L1.

[0050] As described above, the film heater 10 of the first embodiment is configured as described. Next, the heat generated by the film heater 10 will be explained.

[0051] Here, the first electrode 41 is the positive electrode and the second electrode 42 is the negative electrode. Therefore, when a power supply (not shown) supplies power to the film heater 10, current flows from the power supply (not shown) through the first terminal portion 431 and the first lead portion 421 to the first connection portion 411. Furthermore, current flows from the first connection portion 411 through the transparent conductive film 30 to the second connection portion 412. At this time, current flows in one direction, in this case to the right, within the transparent conductive film 30. As a result, the transparent conductive film 30 generates heat.

[0052] As described above, the film heater 10 generates heat. Next, we will explain how localized heat generation in the transparent conductive film 30 is suppressed.

[0053] Here, as a comparative example, we assume that the first connection portion 411 is connected to the first hypotenuse portion 311 and the second hypotenuse portion 312, as shown in Figure 10. We also assume that the first lead portion 421 is connected to the upper bottom portion 301 and the first connection portion 411. Furthermore, we assume that the second connection portion 412 is connected to a part of the lower bottom portion 302. We also assume that the second lead portion 422 is connected to the lower bottom portion 302 and the second connection portion 412. In this case, when a power supply (not shown) supplies power to the film heater 10, current flows downward through the transparent conductive film 30 between the first connection portion 411 and the second connection portion 412, causing the transparent conductive film 30 to generate heat. However, in this case, in the vertical direction, the distance between the first connection portion 411 and the second connection portion 412 on the lower bottom portion 302 side is smaller than the distance between the first connection portion 411 and the second connection portion 412 on the upper bottom portion 301 side.

[0054] Furthermore, the power density Wρ, which is the power per unit area, is expressed as shown in the following relation (1). Therefore, when the voltage applied to the transparent conductive film 30 and the sheet resistance of the transparent conductive film 30 are fixed, the power density Wρ increases as the distance between the first connection part 411 and the second connection part 412 decreases. Here, V is the voltage applied to the transparent conductive film 30. Rs is the sheet resistance of the transparent conductive film 30. Sheet resistance is the electrical resistance per unit area. H is the distance between the first connection part 411 and the second connection part 412.

[0055]

number

[0056] Therefore, in the comparative example film heater shown in Figure 10, as described above, the distance between the first connection part 411 and the second connection part 412 on the lower bottom 302 side is smaller than the distance between the first connection part 411 and the second connection part 412 on the upper bottom 301 side. Furthermore, it is assumed that the voltage applied to the transparent conductive film 30 and the sheet resistance of the transparent conductive film 30 are fixed. Thus, in this case, in the comparative example film heater, the power density Wρ between the first connection part 411 and the second connection part 412 on the lower bottom 302 side is greater than the power density Wρ between the first connection part 411 and the second connection part 412 on the upper bottom 301 side. Consequently, localized heating is likely to occur within the transparent conductive film 30 between the first connection part 411 and the second connection part 412 on the lower bottom 302 side.

[0057] In contrast, in the film heater 10 of this embodiment, as shown in Figures 3 and 5, the lower bottom length Ld is greater than the upper bottom length Lu, that is, the upper bottom length Lu is smaller than the lower bottom length Ld. Also, the first connection part 411 is connected to the first slanted side part 311. Furthermore, the second connection part 412 is connected to the second slanted side part 312. The transparent conductive film 30 generates heat when current flows in one direction, in this case to the right, between the first connection part 411 and the second connection part 412. Furthermore, the upper bottom length Lu is greater than the first shortest distance Lmin1 and the second shortest distance Lmin2. Note that the upper bottom length Lu corresponds to the length of the first bottom in one direction. Also, the lower bottom length Ld corresponds to the length of the second bottom in one direction. Furthermore, the first shortest distance Lmin1 and the second shortest distance Lmin2 correspond to the shortest distance from the second bottom to the first connection part 411 and the second connection part 412.

[0058] As a result, the upper base length Lu is relatively large, which suppresses the relatively small distance between the first connection part 411 and the second connection part 412. Therefore, the localized increase in power density Wρ within the transparent conductive film 30 between the first connection part 411 and the second connection part 412 is suppressed. Consequently, localized heat generation of the transparent conductive film 30 is suppressed.

[0059] Furthermore, the film heater 10 of the first embodiment also provides the following effects.

[0060] [1] When the film heater 10 is viewed from the outside, the first connection portion 411, the second connection portion 412, the first lead portion 421, and the second lead portion 422 are made of metals such as gold, platinum, silver, copper, and aluminum, and therefore stand out more than the transparent conductive film 30 in appearance.

[0061] In contrast, in the film heater 10 of this embodiment, as shown in Figure 4, the first connection portion 411 overlaps with the projected first shielding portion 7 when the first shielding portion 7 is projected in the thickness direction DT. Also, the second connection portion 412 overlaps with the projected second shielding portion 9 when the second shielding portion 9 is projected in the thickness direction DT. Furthermore, the first lead portion 421 overlaps with the projected first shielding portion 7 when the first shielding portion 7 is projected in the thickness direction DT. Also, the second lead portion 422 overlaps with the projected second shielding portion 9 when the second shielding portion 9 is projected in the thickness direction DT.

[0062] As a result, when the film heater 10 is viewed from the outside, the first connection portion 411, the second connection portion 412, the first lead portion 421, and the second lead portion 422 are hidden by the first shielding portion 7 and the second shielding portion 9, making them difficult to see. Therefore, the first connection portion 411, the second connection portion 412, the first lead portion 421, and the second lead portion 422 do not stand out in appearance. Consequently, the deterioration of the design of the film heater 10 is suppressed.

[0063] [2] The first lead length L1 and the second lead length L2 are greater than the upper bottom length Lu. The first lead length L1 and the second lead length L2 correspond to the lengths from the first terminal portion 431 and the second terminal portion 432 to the first bottom in a direction perpendicular to the unidirectional and thickness direction DT.

[0064] This allows for a relatively large space between the upper base 301 and the first terminal section 431 and the second terminal section 432. As a result, peripheral components and devices related to the camera 5 can be more easily placed between the upper base 301 and the first terminal section 431 and the second terminal section 432. Consequently, the mounting capacity of peripheral components and devices is improved.

[0065] [3] The electrical resistance of the first end 461 is greater than that of the second end 462. Also, the electrical resistance of the third end 463 is greater than that of the fourth end 464. Note that the first end 461 corresponds to the first bottom end of the first connection 411. The second end 462 corresponds to the second bottom end of the first connection 411. The third end 463 corresponds to the first bottom end of the second connection 412. The fourth end 464 corresponds to the second bottom end of the second connection 412.

[0066] As a result, the electrical resistance between the first connection part 411 and the second connection part 412 on the upper bottom part 301 is greater than the electrical resistance between the first connection part 411 and the second connection part 412 on the lower bottom part 302. Therefore, current flows less easily between the first connection part 411 and the second connection part 412 on the upper bottom part 301 than between the first connection part 411 and the second connection part 412 on the lower bottom part 302. Consequently, the amount of heat generated between the first connection part 411 and the second connection part 412 on the upper bottom part 301 is less than the amount of heat generated between the first connection part 411 and the second connection part 412 on the lower bottom part 302. Also, the upper bottom length Lu is smaller than the lower bottom length Ld. Therefore, the variation in the amount of heat generated per unit length within the transparent conductive film 30 is reduced. As a result, the temperature within the transparent conductive film 30 tends to become more uniform. Consequently, the temperature variation within the transparent conductive film 30 is reduced.

[0067] [4] The first connecting portion 411 has a plurality of first corrugated portions 441 that are connected to each other and arranged in a row. The second connecting portion 412 has a plurality of second corrugated portions 442 that are connected to each other and arranged in a row.

[0068] As a result, when the length of the first hypotenuse 311 is fixed, the length of the current path through the first connection 411 can be increased compared to when the first connection 411 is a uniform planar shape extending in the direction along the first hypotenuse 311. Furthermore, when the length of the second hypotenuse 312 is fixed, the length of the current path through the second connection 412 can be increased compared to when the second connection 412 is a uniform planar shape extending in the direction along the second hypotenuse 312. Therefore, it becomes easier to adjust the length of the current paths through the first connection 411 and the second connection 412. Consequently, it becomes easier to adjust the electrical resistance of the first connection 411 and the second connection 412.

[0069] (Second Embodiment) In the second embodiment, as shown in Figure 11, the transparent conductive film 30 does not have a first intermediate portion 321 and a second intermediate portion 322, and the lower bottom portion 302 is connected to the first hypotenuse portion 311 and the second hypotenuse portion 312. Therefore, the transparent conductive film 30 is formed in a trapezoidal shape. In addition, the first connecting portion 411 is connected to the boundary between the upper bottom portion 301 and the first hypotenuse portion 311 and to the first hypotenuse portion 311, as well as to the boundary between the first hypotenuse portion 311 and the lower bottom portion 302. Furthermore, the second connecting portion 412 is connected to the boundary between the upper bottom portion 301 and the second hypotenuse portion 312 and to the second hypotenuse portion 312, as well as to the boundary between the second hypotenuse portion 312 and the lower bottom portion 302. Therefore, the first shortest distance Lmin1 and the second shortest distance Lmin2 are set to zero.

[0070] As described above, the film heater 10 of the second embodiment is configured as described above. This second embodiment also provides the same effects as the first embodiment.

[0071] (Other embodiments) This disclosure is not limited to the embodiments described above, and modifications can be made to these embodiments as appropriate. Furthermore, it goes without saying that, in each of the embodiments described above, the elements constituting the embodiment are not necessarily essential, except in cases where they are explicitly stated to be particularly essential or where they are clearly considered essential in principle.

[0072] In each of the above embodiments, the film heater 10 de-ices, melts snow, and prevents fogging of the windshield 3, but is not limited to this. The film heater 10 may also de-ic and melt snow and prevent fogging of radar devices, Lidar and headlights, etc., mounted on the vehicle 1 (not shown). Lidar is an abbreviation for Light Detection and Ranging / Laser Imaging Detection and Ranging.

[0073] Furthermore, the film heater 10 is not limited to being used in the vehicle 1, and may be used in, for example, equipment not shown.

[0074] In each of the above embodiments, the upper base portion 301 is connected to the first slanted edge portion 311. In contrast, an intermediate portion may be formed between the upper base portion 301 and the first slanted edge portion 311, which is connected to the upper base portion 301 and the first slanted edge portion 311, and which extends in a direction intersecting the direction in which the upper base portion 301 and the first slanted edge portion 311 extend.

[0075] Furthermore, the upper base portion 301 and the second slanted side portion 312 are connected. In contrast, an intermediate portion may be formed between the upper base portion 301 and the second slanted side portion 312, which is connected to the upper base portion 301 and the second slanted side portion 312, and which extends in a direction intersecting the direction in which the upper base portion 301 and the second slanted side portion 312 extend.

[0076] In each of the above embodiments, the first electrode 41 is the positive electrode and the second electrode 42 is the negative electrode. Alternatively, the first electrode 41 may be the negative electrode and the second electrode 42 may be the positive electrode.

[0077] In each of the above embodiments, the first connecting portion 411 and the second connecting portion 412 are formed in a meandering shape by having a first wavy portion 441 and a second wavy portion 442, respectively. However, the first connecting portion 411 and the second connecting portion 412 are not limited to being formed in a meandering shape. The first connecting portion 411 may be formed in a uniform planar shape extending in the direction along the first hypotenuse portion 311. Similarly, the second connecting portion 412 may be formed in a uniform planar shape extending in the direction along the second hypotenuse portion 312. Furthermore, the corners of the first wavy portion 441 and the second wavy portion 442 may be chamfered with C-chamfers or R-chamfers.

[0078] The above embodiments may be combined as appropriate.

[0079] (Perspective of this disclosure) [Perspective 1] It is a film heater, A transparent conductive film (30) having a first bottom portion (301) extending in one direction, a second bottom portion (302) facing the first bottom portion in a direction perpendicular to the one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in the one direction greater than the length (Lu) of the first bottom portion in the one direction, a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting the one direction, and a second slanted edge portion (312) connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting the one direction, A first electrode (41) having a first connecting portion (411) connected to the first hypotenuse, A second electrode (42) having a second connecting portion (412) connected to the second hypotenuse, Equipped with, The transparent conductive film transmits electromagnetic waves and generates heat when an electric current flows in one direction within the transparent conductive film between the first and second connection portions. A film heater in which the length (Lu) of the first bottom in one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connection points. [Perspective 2] The aforementioned film heater is attached to a transparent body (3) that transmits electromagnetic waves, The transparent body has a first shielding portion (7) and a second shielding portion (9) that shield electromagnetic waves, When the first shielding portion is projected in the thickness direction, the first connecting portion overlaps with the projected first shielding portion. The film heater according to viewpoint 1, wherein the second connecting portion overlaps with the projected second shielding portion when the second shielding portion is projected in the thickness direction. [Perspective 3] The first electrode is, The first lead portion (421) connected to the first connection portion, A first terminal section (431) is connected to the first lead section and is also connected to a power supply, It has, The second electrode is The second lead portion (422) connected to the second connection portion, A second terminal (432) is connected to the second lead portion and is also connected to the power supply, It has, A film heater according to viewpoint 1 or 2, wherein the lengths (L1, L2) from the first terminal portion and the second terminal portion to the first bottom portion in the direction perpendicular to the aforementioned one direction and the thickness direction are greater than the length (Lu) to the first bottom portion in the aforementioned one direction. [Perspective 4] A film heater according to any one of viewpoints 1 to 3, wherein the electrical resistance of the first bottom-side end (461) of the first connection portion is greater than the electrical resistance of the second bottom-side end (462) of the first connection portion. [Perspective 5] A film heater according to any one of viewpoints 1 to 4, wherein the electrical resistance of the first bottom-side end (463) of the second connection portion is greater than the electrical resistance of the second bottom-side end (464) of the second connection portion. [Perspective 6] The first connecting portion has a plurality of corrugated portions (441) that are connected to each other and arranged in a row. The aforementioned wavy portion is A first extension (451) extending in the direction in which the surface of the transparent conductive film extends, A second extension (452) is connected to the first extension and extends in a direction intersecting the direction in which the first extension extends, A third extension (453) is connected to the second extension and extends in a direction intersecting the direction in which the second extension extends, The fourth extension (454) is connected to the third extension and extends in a direction intersecting the direction in which the third extension extends, and is opposite to the direction in which the second extension and the first extension extend. Includes, A film heater according to any one of viewpoints 1 to 5, wherein the end of the fourth extension opposite to the third extension (4540) is connected to the end of the adjacent corrugated portion of the first extension opposite to the second extension (4510), so that adjacent corrugated portions are connected and lined up. [perspective 7] The aforementioned wavy portion is a first wavy portion, The second connecting portion has a plurality of second corrugated portions (442) that are connected to each other and arranged in a row. The second wavy portion is, A fifth extension (455) extending in the direction in which the surface of the transparent conductive film extends, A sixth extension (456) is connected to the fifth extension and extends in a direction intersecting the direction in which the fifth extension extends, A seventh extension (457) is connected to the sixth extension and extends in a direction intersecting the direction in which the sixth extension extends, The 8th extension (458) is connected to the 7th extension and extends in a direction intersecting the direction in which the 7th extension extends, and is opposite to the direction in which the 6th extension and the 5th extension extend. Includes, The film heater according to viewpoint 6, wherein the end of the eighth extension opposite to the seventh extension (4580) is connected to the end of the fifth extension of the adjacent second corrugated portion (4550) opposite to the sixth extension, so that adjacent second corrugated portions are connected and lined up. [Perspective 8] The aforementioned film heater is attached to a transparent body (3) that transmits electromagnetic waves, The transparent body has a first shielding portion (7) and a second shielding portion (9) that shield electromagnetic waves, The first electrode is, The first lead portion (421) connected to the first connection portion, A first terminal section (431) is connected to the first lead section and is also connected to a power supply, It has, The second electrode is The second lead portion (422) connected to the second connection portion, A second terminal (432) is connected to the second lead portion and is also connected to the power supply, It has, When the first shielding portion is projected in the thickness direction, the first lead portion overlaps with the projected first shielding portion. The film heater according to any one of viewpoints 1, 4 to 7, wherein the second lead portion overlaps with the projected second shielding portion when the second shielding portion is projected in the thickness direction. [Explanation of symbols]

[0080] 10 Film Heater 30 Transparent conductive film 301 Upper bottom 302 Lower bottom 311 First hypotenuse 312 Second hypotenuse 41 1st electrode 411 First connection section 42 2nd electrode 412 Second connection section

Claims

1. It is a film heater, A transparent conductive film (30) having: a first bottom portion (301) extending in one direction; a second bottom portion (302) facing the first bottom portion in a direction perpendicular to the one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in the one direction greater than the length (Lu) of the first bottom portion in the one direction; a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting the one direction; and a second slanted edge portion (312) connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting the one direction; A first electrode (41) having a first connecting portion (411) connected to the first hypotenuse, A second electrode (42) having a second connecting portion (412) connected to the second hypotenuse, Equipped with, The transparent conductive film transmits electromagnetic waves and generates heat when an electric current flows in one direction within the transparent conductive film between the first and second connection portions. The length (Lu) of the first bottom in the aforementioned one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connection parts. A film heater in which the electrical resistance of the first bottom end (461) of the first connection portion is greater than the electrical resistance of the second bottom end (462) of the first connection portion.

2. A film heater, A transparent conductive film (30) having: a first bottom portion (301) extending in one direction; a second bottom portion (302) facing the first bottom portion in a direction perpendicular to the one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in the one direction greater than the length (Lu) of the first bottom portion in the one direction; a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting the one direction; and a second slanted edge portion (312) connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting the one direction; A first electrode (41) having a first connecting portion (411) connected to the first hypotenuse, A second electrode (42) having a second connecting portion (412) connected to the second hypotenuse, Equipped with, The transparent conductive film transmits electromagnetic waves and generates heat when an electric current flows in one direction within the transparent conductive film between the first and second connection portions. The length (Lu) of the first bottom in the aforementioned one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connection parts. A film heater in which the electrical resistance of the end portion (463) on the first bottom side of the second connection portion is greater than the electrical resistance of the end portion (464) on the second bottom side of the second connection portion.

3. A film heater, A transparent conductive film (30) having: a first bottom portion (301) extending in one direction; a second bottom portion (302) facing the first bottom portion in a direction perpendicular to the one direction and the thickness direction (DT) of the film heater, and having a length (Ld) in the one direction greater than the length (Lu) of the first bottom portion in the one direction; a first slanted edge portion (311) connected to the first bottom portion and extending in a direction intersecting the one direction; and a second slanted edge portion (312) connected to the part of the first bottom portion opposite to the first slanted edge portion and extending in a direction intersecting the one direction; A first electrode (41) having a first connecting portion (411) connected to the first hypotenuse, A second electrode (42) having a second connecting portion (412) connected to the second hypotenuse, Equipped with, The transparent conductive film transmits electromagnetic waves and generates heat when an electric current flows in one direction within the transparent conductive film between the first and second connection portions. The length (Lu) of the first bottom in the aforementioned one direction is greater than the shortest distance (Lmin1, Lmin2) from the second bottom to the first and second connection parts. The first connecting portion has a plurality of corrugated portions (441) that are connected to each other and arranged in a row, The aforementioned wavy portion is A first extension (451) extending in the direction in which the surface of the transparent conductive film extends, A second extension (452) is connected to the first extension and extends in a direction intersecting the direction in which the first extension extends, A third extension (453) is connected to the second extension and extends in a direction intersecting the direction in which the second extension extends, The fourth extension (454) is connected to the third extension and extends in a direction intersecting the direction in which the third extension extends, and is opposite to the direction in which the second extension and the first extension extend. Includes, A film heater in which adjacent corrugated portions are connected and arranged side by side, such that the end of the fourth extension opposite to the third extension (4540) is connected to the end of the first extension opposite to the second extension (4510) in the adjacent corrugated portion.

4. The aforementioned wavy portion is a first wavy portion, The second connecting portion has a plurality of second corrugated portions (442) that are connected to each other and arranged in a row. The second wavy portion is, A fifth extension (455) extending in the direction in which the surface of the transparent conductive film extends, A sixth extension (456) is connected to the fifth extension and extends in a direction intersecting the direction in which the fifth extension extends, A seventh extension (457) is connected to the sixth extension and extends in a direction intersecting the direction in which the sixth extension extends, The eighth extension (458) is connected to the seventh extension and extends in a direction intersecting the direction in which the seventh extension extends, and is opposite to the direction in which the sixth extension and the fifth extension extend. Includes, The film heater according to claim 3, wherein the end of the eighth extension opposite to the seventh extension (4580) is connected to the end of the fifth extension of the adjacent second corrugated portion (4550) opposite to the sixth extension, so that adjacent second corrugated portions are connected and lined up.

5. The aforementioned film heater is attached to a transparent body (3) that transmits electromagnetic waves, The transparent body has a first shielding portion (7) and a second shielding portion (9) that shield electromagnetic waves, When the first shielding portion is projected in the thickness direction, the first connecting portion overlaps with the projected first shielding portion. The film heater according to any one of claims 1 to 4, wherein the second connecting portion overlaps with the projected second shielding portion when the second shielding portion is projected in the thickness direction.

6. The first electrode is The first lead portion (421) connected to the first connection portion, A first terminal (431) is connected to the first lead portion and is also connected to a power supply, It has, The second electrode is, The second lead portion (422) connected to the second connection portion, A second terminal (432) is connected to the second lead portion and is also connected to the power supply, It has, The film heater according to any one of claims 1 to 4, wherein the lengths (L1, L2) from the first terminal portion and the second terminal portion to the first bottom portion in the direction perpendicular to the one direction and the thickness direction are greater than the length (Lu) of the first bottom portion in the one direction.

7. The aforementioned film heater is attached to a transparent body (3) that transmits electromagnetic waves, The transparent body has a first shielding portion (7) and a second shielding portion (9) that shield electromagnetic waves, The first electrode is The first lead portion (421) connected to the first connection portion, A first terminal (431) is connected to the first lead portion and is also connected to a power supply, It has, The second electrode is, The second lead portion (422) connected to the second connection portion, A second terminal (432) is connected to the second lead portion and is also connected to the power supply, It has, When the first shielding portion is projected in the thickness direction, the first lead portion overlaps with the projected first shielding portion. The film heater according to any one of claims 1 to 4, wherein the second lead portion overlaps with the projected second shielding portion when the second shielding portion is projected in the thickness direction.

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