Conductive film and heater using the same

Abstract

This optimizes the efficiency of materials used to form the protective layer while ensuring the protective performance for the wiring. [Solution] The conductive film 1 comprises an insulator 2 having a groove 5 that opens upward, wiring 10 having a conductor 12 embedded in the groove 5, and a protective layer 17 laminated on the upper surface side of the conductor 10. The vertical length (dimension D2) between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is greater than the vertical length (dimension D1) between the uppermost surface of the insulator 12 and the upper surface 17a of the protective layer 17.

Description

Technical Field

[0001] The present disclosure relates to a conductive film and a heater using the same.

Background Art

[0002] Conventionally, regarding conductive films, for example, the technology disclosed in Patent Document 1 is known.

[0003] Specifically, Patent Document 1 discloses a conductive film for a touch panel. The conductive film includes a transparent insulating substrate, wirings (metal fine wires) formed on the transparent insulating substrate, and a protective layer formed on the transparent insulating substrate and covering at least a part of the surface of the wirings. The wirings have a tip surface directed toward the side opposite to the transparent insulating substrate and a side surface extending from the edge of the tip surface to the transparent insulating substrate, and include a narrow portion having a line width smaller than the line width of the tip surface. The protective layer covers the side surface of the wirings at a height of 50% or more of the wirings and covers the tip surface of the wirings with a thickness of 1 nm to 5 μm.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conductive film of Patent Document 1, since the protective layer covers the tip surface and the side surface of the wirings, the thickness of the protective layer formed on the transparent insulating substrate naturally becomes large. As a result, in the conductive film, the usage efficiency of the material for forming the protective layer decreases.

[0006] On the other hand, in the conductive film described in Patent Document 1, if the efficiency of using the material forming the protective layer is increased, the thickness of the protective layer covering the leading edge of the wiring becomes smaller. In such cases, the protective performance of the protective layer over the leading edge of the wiring deteriorates.

[0007] Furthermore, Figure 5 of Patent Document 1 discloses a configuration in which the protective layer covers the leading edge of the wiring and a portion of the side surface of the wiring (50% or more but less than 100% of the height of the side surface of the wiring) in order to improve the efficiency of using the material that forms the protective layer. However, in such a configuration, irregularities occur on the upper surface of the conductive film (the surface on the visible side of the conductive film) due to the positional relationship between the parts where the wiring is located and the parts where the wiring is not located. As a result, the appearance of the conductive film is impaired. Moreover, the optical properties of the conductive film deteriorate due to the above-mentioned irregularities.

[0008] Thus, with the conductive film described in Patent Document 1, it was difficult to optimize the efficiency of the material used to form the protective layer while ensuring the protective performance of the protective layer over the wiring.

[0009] This disclosure has been made in view of the above, and its purpose is to optimize the efficiency of the material used to form the protective layer, while also ensuring the protective performance for the wiring. [Means for solving the problem]

[0010] To achieve the above objective, one embodiment of the present disclosure is a conductive film comprising an insulator having a groove opening upward, wiring having a conductor embedded in the groove, and a protective layer laminated on the upper surface side of the conductor. The vertical length between the upper surface of the wiring and the upper surface of the protective layer is greater than the vertical length between the uppermost surface of the insulator and the upper surface of the protective layer. [Effects of the Invention]

[0011] According to this disclosure, it is possible to optimize the efficiency of the material used to form the protective layer while ensuring protective performance for the wiring. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic front view showing a configuration in which the conductive film (heater) according to the present disclosure is provided on the entire surface of the windshield of an automobile, and a plan view showing a partially enlarged view of the structure of the conductive film. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a partially enlarged view of the cross-sectional structure of the conductive film according to Modification 1. [Figure 4] Figure 4 is a partially enlarged view of the cross-sectional structure of the conductive film according to Modification 2. [Figure 5] Figure 5 is a partially enlarged view of the cross-sectional structure of the conductive film according to the reference embodiment. [Modes for carrying out the invention]

[0013] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The following description of embodiments is illustrative in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0014] Figure 1 shows a conductive film 1 according to an embodiment of the present disclosure. The conductive film 1 shown in Figure 1 is used as a heater 101 that can be placed, for example, on the windshield FG of an automobile. The conductive film 1 (heater 101) shown in Figure 1 is placed over the entire surface of the windshield FG in an automobile 100, for example. Specifically, the conductive film 1 (heater 101) is attached to the windshield FG via an adhesive (not shown), such as OCA.

[0015] Note that the conductive film 1 according to the embodiment of the present disclosure is not limited to the use of the heater illustrated in FIG. 1, and can be widely applied to various technical fields such as touch sensors, liquid crystal display devices, organic electroluminescence display devices (OLEDs), micro-LED display devices, solar cell devices, heater devices, antenna devices, electromagnetic shielding sheets, and the like.

[0016] In the following description, the side where the later-described first insulator 3 shown in FIG. 2 is located (the lower side of the paper surface in FIG. 2) is defined as the "lower side" of the conductive film 1, and the side where the later-described second insulator 4 is located (the upper side of the paper surface in FIG. 2) is defined as the "upper side" of the conductive film 1, and the positional relationship of each element constituting the conductive film 1 is determined. Note that such a positional relationship is independent of the actual vertical direction in the device or apparatus on which the conductive film 1 is mounted.

[0017] (Insulator) As shown in FIGS. 1 and 2, the conductive film 1 includes an insulator 2. The insulator 2 has transparency.

[0018] Note that the conductive film 1 does not necessarily have to have transparency. For example, when the conductive film 1 is attached to a housing not shown, there may be a case where, in terms of appearance, it is impossible to distinguish between the housing and the conductive film 1. In such a case, the conductive film 1 may have the same color as the color of the housing. Further, when the conductive film 1 does not have transparency, the visibility of the wiring 10 is also suppressed.

[0019] The insulator 2 is formed in a sheet shape. The thickness of the insulator 2 is, for example, 25 μm or more and 200 μm or less.

[0020] As shown in FIG. 2, the insulator 2 has a first insulator 3 and a second insulator 4.

[0021] The first insulator 3 is made of a resin material having transparency. Examples of the resin material having transparency include resin materials such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), COP (cycloolefin polymer), COC (cycloolefin copolymer), PMMA (polymethyl methacrylate resin), and PI (polyimide). Note that the first insulator 3 does not necessarily have to have transparency.

[0022] The second insulator 4 is laminated on the upper surface 3a side of the first insulator 3. The second insulator 4 is made of a resin material having insulation and permeability. The thickness of the second insulator 4 is larger than the depth of the groove portion 5 (dimension GD shown in FIG. 2) described later. Note that the second insulator 4 does not necessarily have to have transparency.

[0023] (Groove portion) As shown in FIG. 2, a groove portion 5 is provided on the upper surface of the insulator 2 (the upper surface 4a of the second insulator 4). The groove portion 5 has a bottomed shape recessed from the upper surface 4a of the second insulator 4 in the thickness direction of the second insulator 4. The depth (dimension GD) of the groove portion 5 is set, for example, to be 0.2 μm or more and 5.0 μm or less.

[0024] Note that a plurality of groove portions 5 are provided in the conductive film 1 according to this embodiment. The groove widths of the respective groove portions 5 may be the same as each other or may be different from each other.

[0025] The groove portion 5 has a bottom surface 5a and groove side surfaces 5b. Here, the "groove side surfaces 5b" are surfaces of the insulator 2 that form the groove portion 5 and are non-parallel to the upper surface of the insulator 2 (the upper surface 4a of the second insulator 4).

[0026] The groove side surface 5b is formed in a tapered shape, widening upward (towards the opening side of the groove 5) from the lower surface 5a of the groove 5. Specifically, in the thickness direction of the insulator 2, the groove side surface 5b is inclined upward (towards the opening side of the groove 5) from the lower surface 5a of the groove 5 to the left or right side of the paper in Figure 2. As a result, in this embodiment, the groove width dimension GW1 at the opening of the groove 5 is larger than the width dimension GW2 at the lower surface 5a of the groove 5.

[0027] The groove width dimension GW1 of the groove 5 is, for example, 0.5 μm or more and 20 μm or less. The aspect ratio of the groove 5 shown in Figure 2 (the value obtained by dividing the depth dimension GD in the groove 5 by the groove width dimension GW1) is, for example, 0.1 or more.

[0028] (wiring) As shown in Figures 1 and 2, the conductive film 1 includes wiring 10. Specifically, the conductive film 1 according to this embodiment includes a plurality of wirings 10 (see Figure 1). The wiring 10 is formed in the shape of a fine wire. The line width of the wiring 10 is, for example, 0.5 μm or more and 20 μm or less.

[0029] The wiring 10 is formed in a straight line. The wiring 10 extends diagonally with respect to the X and Y directions shown in Figure 1. Multiple wirings 10 are arranged with space between them.

[0030] Note that the wiring 10 is not limited to being straight. For example, although not shown in the figures, the wiring 10 may be formed in a curved shape. Also, a plurality of wirings 10 may include both straight wirings 10 and curved wirings 10. Furthermore, the wiring 10 may extend in the X and Y directions as shown in Figure 1.

[0031] The conductive film 1 comprises a plurality of cells 11. Each cell 11 is formed in a closed manner by a plurality of wirings 10. The cells in this embodiment have a rhombus shape. However, the shape of the cell 11 is not limited to a rhombus, and may be other polygonal shapes (triangle, square, etc.) or circular shapes.

[0032] (conductor) As shown in Figure 2, the wiring 10 has a conductor 12. The conductor 12 is embedded in the groove 5. The conductor 12 is laminated, for example, to an adhesion layer 13 and a seed layer 14 provided within the groove 5.

[0033] The adhesion layer 13 is an element that ensures the adhesion of the seed layer 14 to the groove 5. The adhesion layer 13 is a metal layer composed of a metal nitride or metal oxide containing at least one metal selected from the group consisting of Ti, Ni, Al, V, W, Ta, Si, Cr, Ag, Mo, Cu, and Zn. The adhesion layer 13 may be a single layer or a laminate of multiple layers with different compositions. The adhesion layer 13 is deposited in a thin film form on the bottom surface 5a and groove side surface 5b in the groove 5, for example, by vapor deposition or sputtering.

[0034] The seed layer 14 has the function of bonding the conductor 12 to the adhesion layer 13. Specifically, in this embodiment, the seed layer 14 functions as a cathode for laminating the conductor 12, which will be described later and may include copper (Cu), onto the adhesion layer 13 during an electroplating process to form the conductor 12. The seed layer 14 is laminated onto the adhesion layer 13 in a thin film form by, for example, vapor deposition or sputtering.

[0035] The conductor 12 is made of a conductive metal such as copper (Cu). The conductor 12 is formed by electroplating, electroless plating, vacuum deposition, etc. When electroplating is performed, the conductor 12 and the seed layer 14 are formed integrally. As a result, the interface between the conductor 12 and the seed layer 14 may become indistinguishable. Although copper (Cu) is suitable as the main component of the wiring 10, other metals (e.g., silver, gold, nickel, aluminum) may also be included.

[0036] (Blackened layer) As shown in Figure 2, the wiring 10 includes a blackened layer 15. The blackened layer 15 has the function of preventing the wiring 10 from being visible when viewed from the upper surface of the insulator 2 (upper surface 4a of the second insulator 4). As will be described later, the blackened layer 15 may be omitted as appropriate depending on the usage conditions of the conductive film 1, if it does not particularly affect the visibility of the conductive film 1.

[0037] The blackened layer 15 is laminated on the upper surface of the conductor 12. From the viewpoint of suppressing the electrical resistance of the wiring 10, the thickness of the blackened layer 15 is preferably, for example, 3 nm or more and 50 nm or less.

[0038] (Indentation) As shown in Figure 2, a recessed portion 16 is formed on the upper surface of the conductor 12, which is recessed downwards. The recessed portion 16 is formed in a curved shape. Specifically, in this embodiment, the recessed portion 16 curves downwards (towards the lower surface 5a of the groove 5) from the upper surface 4a (uppermost surface) of the second insulator 4 as it moves from the groove side surface 5b of the groove 5 toward the center in the groove width direction. The deepest part 16a of the recessed portion 16 is located in the center of the groove width direction of the groove 5.

[0039] In the embodiments of this disclosure, the recessed portion 16 makes it possible to make the thickness of the protective layer 17 (the first protective layer 18 described later) laminated on the upper surface side of the conductor 12 greater than the thickness of the protective layer 17 (the second protective layer 19 described later) laminated on the uppermost surface side of the insulator 2 (the upper surface 4a side of the second insulator 4). As a result, the protective performance of the protective layer 17 over the wiring 10 can be improved.

[0040] (protective layer) As shown in Figure 2, the conductive film 1 includes a protective layer 17. The protective layer 17 is laminated on the upper surface 4a side of the second insulator 4 and on the upper surface side of the conductor 12. In this embodiment, the vertical distance between the upper surface 17a of the protective layer 17 and the lower surface 5a of the groove 5 is greater than the depth (dimension GD) of the groove 5.

[0041] The protective layer 17 is formed by applying an organic material (described later) for forming the protective layer 17 to the upper surface 4a of the second insulator 4 and the upper surface of the wiring 10 (above the blackened layer 15), and then curing the applied organic material. It is possible to adjust the thickness of the protective layer 17 by appropriately setting the amount and viscosity of the organic material applied during the manufacturing process.

[0042] The protective layer 17 contains an organic material. This organic material may be in solution form, dissolved in a solvent. Alternatively, the organic material may be in emulsion form, in which the resins described later are dispersed as particulate matter.

[0043] Examples of the above-mentioned organic materials include silicone resins, vinyl ester resins, and polyimide resins. Other examples of the above-mentioned organic materials include acrylic resins, polyurethane resins, polyolefin resins, polyester resins, vinyl chloride resins, epoxy resins, ethylene-vinyl acetate copolymer resins, polycarbonate resins, phenoxy resins, and terpene resins. These resins may be used individually or as a mixture of two or more types.

[0044] When the above organic material contains a crosslinking agent, preferably the organic material has crosslinkable groups that react with the crosslinking agent. Examples of the above crosslinking agent include oxazoline-based crosslinking agents, carbodiimide-based crosslinking agents, epoxy-based crosslinking agents, isocyanate-based crosslinking agents, melamine-based crosslinking agents, carbodiimide-based crosslinking agents, and oxazoline-based crosslinking agents.

[0045] For the sake of explanation, the portion of the protective layer 17 that overlaps with the groove 5 when viewed from above may be referred to as the "first protective layer 18" below. Also, the portion of the protective layer 17 that overlaps with the top surface of the second insulator 4 when viewed from above may be referred to as the "third protective layer 19".

[0046] As described above, a recessed portion 16 is formed on the upper surface of the conductor 12, which is recessed downwards. Due to this recessed portion 16, during the manufacturing process of the protective layer 17, the organic material applied to the upper surface of the wiring 10 enters the recessed portion 16 of the conductor 12. In other words, a part of the protective layer 17 enters the recessed portion 16 of the conductor 12. Furthermore, the lower surface of the protective layer 17 (first protective layer 18) located above the conductor 12 embedded in the groove 5 is formed in the same curved shape as the recessed portion 16 of the conductor 12.

[0047] On the other hand, the upper surface 17a of the protective layer 17 is formed in a flat shape. Furthermore, the flat upper surface of the first protective layer 18 and the flat upper surface of the third protective layer 19 are flush. This is because, in the manufacturing process of the protective layer 17, by applying the solution-type organic material to the upper surface 4a of the second insulator 4 and the upper surface of the conductor 12, the upper portion of the solution-type organic material (the portion of the organic material located on the opposite side of the side that contacts the upper surface 4a of the second insulator 4 and the upper surface of the conductor 12) hardens in a flat shape regardless of the position of the depression 16. Note that "flat shape" means that there are no irregularities on the upper surface 17a of the protective layer 17 on the order of μm (generally, between 0.1 μm and 1000 nm).

[0048] Thus, in the embodiments of this disclosure, by including an organic material in the protective layer 17, the constituent material of the protective layer 17 can be, for example, a solution type in which the organic material exists dissolved in a solvent. When this solution type is used, as described above, irregularities are less likely to occur on the upper surface of the conductive film 1 (i.e., the upper surface 17a of the protective layer 17 located on the visible side of the conductive film 1). As a result, the appearance of the conductive film 1 is not impaired, and the optical properties of the conductive film 1 can be guaranteed.

[0049] (Characteristic structure) A characteristic configuration of the conductive film 1 according to the embodiment of this disclosure is that the vertical length (dimension D2) between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is greater than the vertical length (dimension D1) between the uppermost surface of the insulator 2 and the upper surface 17a of the protective layer 17. The "uppermost surface of the insulator 2" corresponds to the upper surface 4a of the second insulator 4 shown in Figure 2.

[0050] The vertical length between the uppermost surface of the insulator 2 and the upper surface 17a of the protective layer 17 corresponds to the length D1 shown in Figure 2. Length D1 corresponds to the thickness of the third protective layer 19. Preferably, length D1 is 0.1 μm or more and 50 μm or less.

[0051] The maximum vertical length between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is the length D2 shown in Figure 2. Length D2 corresponds to the maximum thickness of the first protective layer 18. That is, length D2 corresponds to the vertical length between the deepest part 16a of the recess 16 and the upper surface of the first protective layer 18. Preferably, length D2 is 0.1 μm or more and 50 μm or less.

[0052] In the embodiments of this disclosure, since the conductor 12 of the wiring 10 is embedded in the groove 5 of the insulator 2, the protective layer 17 does not need to cover the sides of the conductor 12, and the conductor 12 of the wiring 10 can be adequately protected by the protective layer 17 laminated on the upper surface side of the conductor 12. As a result, unlike the conventional technology described above (conductive film of Patent Document 1), the conductive film 1 can improve the efficiency of the material used to form the protective layer 17.

[0053] Furthermore, as described above, the vertical length (dimension D2) between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is greater than the vertical length (dimension D1) between the uppermost surface of the insulator 2 and the upper surface 17a of the protective layer 17. In other words, the thickness of the protective layer 17 (first protective layer 18) laminated on the upper surface side of the conductor 12 is greater than the thickness of the protective layer 17 (third protective layer 19) laminated on the uppermost surface side of the insulator 2. This enhances the protective performance of the protective layer 17 over the wiring 10 (upper surface of the conductor 12).

[0054] Therefore, the conductive film 1 can optimize the efficiency of the material used to form the protective layer 17, while also ensuring protective performance for the wiring 10.

[0055] [Modified Example 1 of the Embodiment] In the above embodiment, the relative sizes of the groove widths in the multiple grooves 5 were not specifically defined, but as shown in Modification 1 in Figure 3, the relative sizes of the groove widths in each groove 5 may be specified. The configuration of the conductive film 1 according to Modification 1 will be described below. In the following description, components of the conductive film 1 that are the same as those in the above embodiment are denoted by the same reference numerals as those in the components shown in Figures 1 and 2.

[0056] (First and second grooves) As shown in Figure 3, the groove 5 of Modified Example 1 has a first groove 21 and a second groove 22. The groove width of the second groove 22 (dimension GW4 shown in Figure 3) is larger than the groove width of the first groove 21 (dimension GW3 shown in Figure 3). The dimension GW3 of the first groove 21 is, for example, 0.5 μm or more and 5 μm or less. The aspect ratio of the first groove 21 is, for example, 0.2 or more. The dimension GW4 of the second groove 22 is, for example, 3 μm or more and 20 μm or less. The aspect ratio of the second groove 22 is, for example, 0.1 or more. Note that in Figure 3, a configuration in which the depth of the first groove 21 and the depth of the second groove 22 are the same (dimension GD shown in Figure 3) is illustrated, but the depths of the first groove 21 and the second groove 22 may be different.

[0057] (First and second wiring) The wiring 10 has a first wiring 23 and a second wiring 24. The first wiring 23 has a first conductor 25 embedded in the first groove 21. The second wiring 24 has a second conductor 26 embedded in the second groove 22. The first and second conductors 25 and 26 both have the same configuration as the conductor 12 shown in the above embodiment. Note that in Figure 3, for ease of illustration, the adhesion layer 13, seed layer 14, and blackening layer 15 shown in the above embodiment are omitted.

[0058] (First and second recessed areas) A first recessed portion 27, which is recessed downwards, is formed on the upper surface of the first conductor 25. A second recessed portion 28, which is recessed downwards, is formed on the upper surface of the second conductor 26.

[0059] Each of the first and second recesses 27 and 28 is formed in a curved shape, similar to the recess 16 in the above embodiment. In this modified example 1, the deepest part 27a of the first recess 27 is located in the center of the groove width direction of the first groove 21. The deepest part 28a of the second recess 28 is located in the center of the groove width direction of the second groove 22.

[0060] The depth from the top surface of insulator 2 (top surface 4a of second insulator 4) to the deepest part 28a of the second recess 28 (dimension D4 shown in Figure 3) is greater than the depth from the top surface of insulator 2 to the deepest part 28a of the first recess 27 (dimension D3 shown in Figure 3). The relationship between the first and second recesses 27, 28 and the protective layer 17 of modified example 1 will be described later.

[0061] (First to third protective layer) As shown in Figure 3, the protective layer 17 of the modified example 1 has first to third protective layers 31 to 33. The first protective layer 31 is the portion of the protective layer 17 that overlaps with the first groove 21 when viewed from above. The second protective layer 32 is the portion of the protective layer 17 that overlaps with the second groove 22 when viewed from above. The third protective layer 33 is the portion of the protective layer 17 that overlaps with the upper surface 4a of the second insulator 4 when viewed from above. The lower limit of the thickness of the third protective layer 33 is 0.05 μm.

[0062] In Modification 1, the upper surface 17a of the protective layer 17 is formed flat, similar to the protective layer 17 in the above embodiment. Specifically, the upper surfaces of each of the first to third protective layers 31 to 33 are formed flat. Furthermore, the upper surfaces of the first to third protective layers 31 to 33 are flush with the surface.

[0063] Although the dimensions are not shown in the diagram, in this modified example 1, the vertical distance between the upper surface of the first protective layer 31 and the lower surface of the first groove 21 is greater than the depth of the first groove 21 (dimension GD). Also, the vertical distance between the upper surface of the second protective layer 32 and the lower surface of the second groove 22 is greater than the depth of the second groove 22 (dimension GD).

[0064] Even in the modified example 1, similar to the embodiment described above, the first and second recesses 27 and 28 make it possible to make the thicknesses of the first and second protective layers 31 and 32 greater than the thickness of the third protective layer 33 laminated on the uppermost side of the insulator 2 (the upper surface 4a side of the second insulator 4). As a result, the protective performance of the first and second protective layers 31 and 32 over the first and second wirings 23 and 24 can be improved.

[0065] Furthermore, as described above, the depth (dimension D4) from the top surface of the insulator 2 (on the side of the top surface 4a of the second insulator 4) to the deepest part 28a of the second recess 28 is greater than the depth (dimension D3) from the top surface of the insulator 2 (on the side of the top surface 4a of the second insulator 4) to the deepest part 27a of the first recess 27. With this configuration, in modified example 1, the thickness of the second protective layer 32 is greater than the thickness of the first protective layer 31. That is, the thickness of the second protective layer 32 covering the top surface of the second wiring 24, which has a relatively large line width, is greater than the thickness of the first protective layer 31 covering the top surface of the first wiring 23, which has a relatively small line width. As a result, in the conductive film 1 according to modified example 2, the efficiency of material usage for forming the protective layer 17 can be optimized, and the protective performance for the second wiring 24, which has a relatively large line width, can be efficiently improved.

[0066] [Modification of Embodiment 2] In the above modified example 1, the protective layer 17 is shown to have first to third protective layers 31-33. However, it is not limited to this form. For example, as shown in modified example 2 in Figure 4, the protective layer 17 may have first and second protective layers 41, 42. Below, the conductive film 1 according to modified example 2 will be mainly described in terms of its configuration which differs from that of modified example 1. In the following description, components that are the same as those in the conductive film 1 according to modified example 1 are denoted by the same reference numerals as those in the configuration shown in Figure 3.

[0067] (First and second recessed areas) As shown in Figure 4, the first and second recesses 43 and 44 of Modified Example 2 have different shapes from the first and second recesses 27 and 28 shown in Modified Example 1.

[0068] The first recessed portion 43 is formed in a concave shape extending downward from the upper surface 4a of the second insulator 4. The first recessed portion 43 is formed in a flat shape. The upper surface of the first protective layer 41 (described later) and the first recessed portion 43 are equally spaced across the entire groove width direction of the first groove 21.

[0069] The second recessed portion 44 is formed in a concave shape extending downward from the upper surface 4a of the second insulator 4. The second recessed portion 44 is formed in a flat shape. The upper surface of the second protective layer 42 (described later) and the second recessed portion 44 are equally spaced across the entire groove width direction of the second groove 22.

[0070] (First and second protective layers) As shown in Figure 4, the protective layer 17 of the modified example 2 has first and second protective layers 41 and 42.

[0071] The first protective layer 41 is the portion of the protective layer 17 that overlaps with the first groove 21 when viewed from above. The upper surface 41a of the first protective layer 41 is formed to be flat. Unlike the first protective layer 31 shown in Modification 1, the first protective layer 41 of Modification 2 is embedded inside the first groove 21.

[0072] The second protective layer 42 is the portion of the protective layer 17 that overlaps with the second groove 22 when viewed from above. The upper surface 42a of the second protective layer 42 is formed to be flat. Unlike the second protective layer 32 shown in the first modified example, the second protective layer 42 in the second modified example 2 is embedded inside the second groove 22.

[0073] In the conductive film 1 according to Modified Example 2, the vertical distance between the upper surface 41a of the first protective layer 41 and the lower surface 21a of the first groove 21 is equal to the depth of the first groove 21 (dimension GD shown in Figure 4). Specifically, in Modified Example 2, the upper surface 41a of the first protective layer 41 is flush with the upper surface 4a of the second insulator 4. With this configuration, the first protective layer 41 does not need to cover the side surface of the first conductor 25, and the upper surface of the first conductor 25 can be appropriately protected by the first protective layer 41 located inside the first groove 21. As a result, the efficiency of using the material forming the first protective layer 41 can be increased.

[0074] Furthermore, the vertical distance between the upper surface 42a of the second protective layer 42 and the lower surface 22a of the second groove 22 is equal to the depth of the second groove 22 (dimension GD shown in Figure 4). Specifically, in modified example 2, the upper surface 42a of the second protective layer 42 is flush with the upper surface 4a of the second insulator 4. With this configuration, the second protective layer 42 does not need to cover the side surface of the second conductor 26, and the upper surface of the second conductor 26 can be properly protected by the second protective layer 42 located inside the second groove 22. As a result, the efficiency of using the material forming the second protective layer 42 can be increased.

[0075] Here, the protective layer 17 shown in Modification 2 does not have a configuration equivalent to the third protective layer 33 shown in Modification 1. Also, in Modification 2, the upper surface 41a of the first protective layer 41 and the upper surface 42a of the second protective layer 42 are flush with the upper surface 4a of the second insulator 4. As a result, the protective layer 17 of Modification 2 can omit the material that forms the third protective layer 33 compared to the protective layer 17 of Modification 1. As a result, the efficiency of the material used to form the protective layer 17 can be further increased. Furthermore, in this modification, by omitting the third protective layer 33 of Modification 1, the overall thickness of the conductive film 1 can be made relatively thinner.

[0076] Furthermore, as a further modification of Modification 2, the protective layer 17 may have a third protective layer (not shown). In this case, from the viewpoint of improving the efficiency of using the material forming the protective layer 17, the distance between the upper surface of the third protective layer (not shown) and the upper surface (topmost surface) of the second insulator 4 should be within the margin of error (for example, a value smaller than 0.05 μm). Even such a protective layer 17 is included within the range of the configuration relating to the conductive film 1 of Modification 2.

[0077] [Example of an embodiment] As a reference example of the embodiment, in the conductive film 200 shown in Figure 5, the first and second recesses 27, 28 shown in Modification 1 above, or the first and second recesses 43, 44 shown in Modification 2 above, do not necessarily have to be formed on the upper surfaces of the first and second conductors 25, 26. Furthermore, in the conductive film 200 of the reference example, the upper surfaces of the first and second conductors 25, 26 may both be flush with the upper surface 4a of the second insulator 4.

[0078] The protective layer 50 in the reference example has first to third protective layers 51 to 53.

[0079] The first protective layer 51 is the portion of the protective layer 50 that overlaps with the first groove 21 when viewed from above. The second protective layer 52 is the portion of the protective layer 50 that overlaps with the second groove 22 when viewed from above. The third protective layer 53 is the portion of the protective layer 50 that overlaps with the upper surface 4a of the second insulator 4 when viewed from above.

[0080] In the example, the upper surface 50a of the protective layer 50 is formed flat. Specifically, the upper surfaces of the first to third protective layers 51 to 53 are formed flat. Furthermore, the upper surfaces of the first to third protective layers 51 to 53 are flush with each other. In the configuration shown in Figure 5, the thicknesses of the first to third protective layers 51 to 53 are approximately the same.

[0081] Even with a conductive film 200 according to such a reference example, since the conductors (first and second conductors 25, 26) are embedded in the grooves (first and second grooves 21, 22) of the insulator 2, the protective layers (first and second protective layers 51, 52) do not need to cover the sides of the conductors, and the wiring can be properly protected by the protective layers laminated on the upper surface of the conductors. As a result, even with a conductive film 200 according to the reference example, the efficiency of using the material forming the protective layer can be increased.

[0082] [Other embodiments] In the above embodiment, the groove side surface 5b of the groove portion 5 is shown to be tapered, but the embodiment is not limited to this form. That is, the groove side surface 5b does not have to be formed in a tapered shape. Specifically, the surface direction of the groove side surface 5b may extend straight upward from the lower surface 5a of the groove portion 5 in the vertical direction (perpendicular to the lower surface 5a) (not shown).

[0083] In the above embodiment, a form having a blackened layer 15 was shown, but the embodiment is not limited to this. That is, if it does not particularly affect the visibility of the conductive film 1, the blackened layer 15 may be omitted as appropriate depending on the usage conditions of the conductive film 1. The same applies to the above modified examples 1 and 2 and the above reference example.

[0084] [summary] As a first disclosure, the conductive film 1 comprises an insulator 2 having a groove 5 that opens upward, wiring 10 having a conductor 12 embedded in the groove 5, and a protective layer 17 laminated on the upper surface side of the conductor 12. The vertical length (dimension D2) between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is greater than the vertical length (dimension D1) between the uppermost surface of the insulator 2 and the upper surface 17a of the protective layer 17.

[0085] In the first disclosure, since the conductor 12 of the wiring 10 is embedded in the groove 5 of the insulator 2, the protective layer 17 does not need to cover the sides of the conductor 12, and the protective layer 17 laminated on the upper surface of the conductor 12 can adequately protect the conductor 12 of the wiring 10. As a result, unlike the conventional technology described above (the conductive film of Patent Document 1), the conductive film 1 according to the first disclosure can improve the efficiency of the material used to form the protective layer 17.

[0086] Furthermore, in the first disclosure, the vertical length between the upper surface of the wiring 10 and the upper surface 17a of the protective layer 17 is greater than the vertical length between the uppermost surface of the insulator 2 and the upper surface 17a of the protective layer 17. That is, the thickness of the protective layer 17 laminated on the upper surface side of the conductor 12 is greater than the thickness of the protective layer 17 laminated on the uppermost surface side of the insulator 2. This enhances the protective performance of the protective layer 17 over the wiring 10 (upper surface of the conductor 12).

[0087] Therefore, the conductive film 1 according to the first disclosure can optimize the efficiency of the material used to form the protective layer 17, and can also ensure protective performance for the wiring 10.

[0088] As a second disclosure, the protective layer 17 includes an organic material.

[0089] In the second disclosure, the constituent material of the protective layer 17 can be, for example, a solution type in which the organic material is dissolved in a solvent. When such a solution type is used, as described above, irregularities are less likely to occur on the upper surface of the conductive film 1 (the surface located on the viewing side of the conductive film 1). As a result, the appearance of the conductive film 1 is not impaired, and the optical properties of the conductive film 1 can be guaranteed.

[0090] As a third disclosure, a recessed portion 16 that is recessed downwards is formed on the upper surface of the conductor 12.

[0091] In this third disclosure, the recess 16 makes it possible to make the thickness of the protective layer 17 laminated on the upper surface side of the conductor 12 greater than the thickness of the protective layer 17 laminated on the uppermost surface side of the insulator 2. As a result, the protective performance of the protective layer 17 over the wiring 10 can be improved.

[0092] As a fourth disclosure, the groove 5 has a first groove 21 and a second groove 22. The wiring 10 has a first wiring 23 and a second wiring 24. The first wiring 23 has a first conductor 25 embedded in the first groove 21. The second wiring 24 has a second conductor 26 embedded in the second groove 22. A first recess 27 that is recessed downward is formed on the upper surface of the first conductor 25. A second recess 28 that is recessed downward is formed on the upper surface of the second conductor 26. The groove width (dimension GW4) of the second groove 22 is greater than the groove width (dimension GW3) of the first groove 21. The depth from the upper surface of the insulator 2 to the deepest part 28a of the second recess 28 is greater than the depth from the upper surface of the insulator 2 to the deepest part 27a of the first recess 27.

[0093] In this fourth disclosure, the thickness of the protective layer 17 covering the upper surface of the second wiring 24, which has a relatively large line width (second protective layer 32 as illustrated in Figure 3), is greater than the thickness of the protective layer 17 covering the upper surface of the first wiring 23, which has a relatively small line width (first protective layer 31 as illustrated in Figure 3). As a result, the conductive film 1 according to the fourth disclosure can optimize the efficiency of the material used to form the protective layer 17, and can efficiently improve the protective performance for the second wiring 24, which has a relatively large line width.

[0094] As a fifth disclosure, the groove 5 has a first groove 21 and a second groove 22. The wiring 10 has a first wiring 23 and a second wiring 24. The first wiring 23 has a first conductor 25 embedded in the first groove 21. The second wiring 24 has a second conductor 26 embedded in the second groove 22. A first recess 43 that is recessed downward is formed on the upper surface of the first conductor 25. A second recess 44 that is recessed downward is formed on the upper surface of the second conductor 26. The groove width (dimension GW4) of the second groove 22 is greater than the groove width (dimension GW3) of the first groove 21. The protective layer 17 has a first protective layer 41 that overlaps with the first groove 21 when viewed from above and a second protective layer 42 that overlaps with the second groove 22 when viewed from above. The vertical distance between the upper surface 41a of the first protective layer 41 and the lower surface 21a of the first groove 21 is equal to the depth (dimension GD) of the first groove 21. The vertical distance between the upper surface 42a of the second protective layer 42 and the lower surface 22a of the second groove 22 is equal to the depth (dimension GD) of the second groove 22.

[0095] In this fifth disclosure, since the vertical distance between the upper surface 41a of the first protective layer 41 and the lower surface 21a of the first groove 21 is equal to the depth of the first groove 21, the first protective layer 41 does not need to cover the side surface of the first conductor 25, and the upper surface of the first conductor 25 can be adequately protected by the first protective layer 41 located inside the first groove 21. Furthermore, since the vertical distance between the upper surface 42a of the second protective layer 42 and the lower surface 22a of the second groove 22 is equal to the depth of the second groove 22, the second protective layer 42 does not need to cover the side surface of the second conductor 26, and the upper surface of the second conductor 26 can be adequately protected by the second protective layer 42 located inside the second groove 22. [Industrial applicability]

[0096] This disclosure has industrial applications as a conductive film and a heater using the same. [Explanation of Symbols]

[0097] 1,200: Conductive film 2: Insulator 3: First insulator 4: Second insulator 5: Groove 10: Wiring 11: Cell 12: Conductors 13: Close contact layer 14: Seed Layer 15: Blackened layer 16: Recess 16a, 27a, 28a: Deepest part 17,50:Protective layer 18,31,41,51: First protective layer 32,42,52:Second protective layer 19,33,43,53:Third protective layer 21:First groove 22:Second groove part 23: First wiring 24:Second wiring 25: First Conductor 26: Second conductor 27: First depression 28: Second depression 100: Automobile FG: Windshield 101: Heater

Claims

1. An insulator having a groove that opens upward, A wire having a conductor embedded in the groove, The conductor comprises a protective layer laminated on the upper surface side, A conductive film in which the vertical length between the upper surface of the wiring and the upper surface of the protective layer is greater than the vertical length between the uppermost surface of the insulator and the upper surface of the protective layer.

2. In the conductive film according to claim 1, The protective layer is a conductive film containing an organic material.

3. In the conductive film according to claim 1 or 2, A conductive film having a recessed portion formed on the upper surface of the conductor that is indented downwards.

4. In the conductive film according to any one of claims 1 to 3, The groove portion has a first groove portion and a second groove portion, The aforementioned wiring has a first wiring and a second wiring, The first wiring has a first conductor embedded in the first groove, The second wiring has a second conductor embedded in the second groove, The upper surface of the first conductor has a first recess formed therein that is indented downwards. The upper surface of the second conductor has a second recess formed therein, which is recessed downwards. The groove width of the second groove is greater than the groove width of the first groove. A conductive film wherein the depth from the upper surface of the insulator to the deepest part of the second recess is greater than the depth from the upper surface of the insulator to the deepest part of the first recess.

5. In the conductive film according to any one of claims 1 to 3, The groove portion has a first groove portion and a second groove portion, The aforementioned wiring has a first wiring and a second wiring, The first wiring has a first conductor embedded in the first groove, The second wiring has a second conductor embedded in the second groove, The upper surface of the first conductor has a first recess formed therein that is indented downwards. The upper surface of the second conductor has a second recess formed therein, which is recessed downwards. The groove width of the second groove is greater than the groove width of the first groove. The protective layer comprises a first protective layer that overlaps with the first groove when viewed from above, and a second protective layer that overlaps with the second groove when viewed from above. The vertical distance between the upper surface of the first protective layer and the lower surface of the first groove is equal to the depth of the first groove. A conductive film in which the vertical distance between the upper surface of the second protective layer and the lower surface of the second groove is equal to the depth of the second groove.

6. A heater using the conductive film described in any one of claims 1 to 5.

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