JP2019009332A - Circuit sheet - Google Patents

Abstract

An object of the present invention is to provide a circuit sheet that does not deteriorate or break the conductivity of a circuit even when a resin film is three-dimensionally stretched.
A circuit sheet 11 has a circuit 13 made of a conductive coating film on a resin film 12, and has a three-dimensionally shaped portion 12a protruding in the thickness direction. The three-dimensionally shaped portion 12 a has a plurality of slits 15 formed along the conductive lines 14 of the circuit 13. The slit 15 can be opened in the extending direction of the resin film 12 forming the three-dimensionally shaped portion 12a, thereby absorbing the elongation of the resin film 12. For this reason, the elongation of the conductive wire 14 can be suppressed.
[Selection] Figure 1

Description

  The present invention relates to a circuit sheet used in various electric devices and the like. More specifically, the present invention relates to a circuit sheet having a circuit formed by a conductive wire of a conductive coating film on a resin film.

  In order to arrange various electronic components and circuits in a compact manner inside a housing of an electronic device, a circuit sheet is used in which circuit wiring is formed on a resin film with conductive wires made of a conductive coating film. Since this circuit sheet uses a thin resin film as a base material, it can be easily deformed, and the resin film can be bent in the thickness direction so that it can be arranged along the three-dimensional shape of the casing of the electronic device. Is formed in a three-dimensional shape by stretching in the plane direction. Such a circuit sheet is described as a three-dimensional molded circuit sheet in, for example, Japanese Patent Application Laid-Open No. 2005-167216 (Patent Document 1).

JP 2005-167216 A

  The three-dimensional circuit sheet is given a three-dimensional shape by bending or stretching the resin film as described above. Therefore, for example, as shown in FIG. 12, when the resin film 1 is three-dimensionally formed and stretched in all directions on the plane, the conductive wires 2 forming the circuit are also stretched in all directions similarly to the resin film 1, The conductive particles contained in the conductive wire 2 spread thinly and the density thereof becomes sparse, which may cause a decrease in conductivity or an electrical disconnection.

  The present invention has been made against the background of the prior art as described above. An object of the present invention is to provide a circuit sheet in which the resin film has a three-dimensionally shaped portion protruding in the thickness direction, and there is no reduction in circuit conductivity or breakage even if the resin film is stretched there. And

  In order to achieve the above object, the present invention provides the following circuit sheet.

  In the present invention, for a circuit sheet having a circuit in which conductive wires of a conductive coating film are formed on a resin film, the resin film has a three-dimensional shape portion protruding in the thickness direction. And a plurality of slits formed adjacent to each other along the conductive line, and the slits are open in the extending direction of the resin film forming the three-dimensionally shaped portion.

  According to the circuit sheet of the present invention, since the circuit in which the conductive wire is formed in the three-dimensional shape portion is formed, it can be configured as a three-dimensional circuit sheet. In the three-dimensional shape portion, a plurality of slits formed adjacent to each other along the conductive line is formed, and the slit is opened in the extending direction of the resin film forming the three-dimensional shape portion, so that the resin film is stretched. A pull in a direction is insulated or relaxed by a slit that opens in that direction. Therefore, when the resin film is stretched, the conductive wire extends in the crossing direction of the conductive wire, so that the electrical resistance is less likely to be broken or broken. As a result, the conductive wire is conductive while having various three-dimensional shapes. A circuit sheet having a good circuit can be realized.

  More specifically, the three-dimensional shape portion of the resin film is three-dimensionally molded by, for example, die molding, so that the conductive wire extends in the direction along the conductive wire, but the slit opens in the crossing direction of the conductive wire. Therefore, the conductive wire is difficult to be stretched and contracts. Therefore, since the conductive wire is not stretched as a whole as compared with the case where the conductive wire is stretched in all directions without a slit, conductivity can be maintained. In a circuit in which a plurality of conductive lines are formed densely, the plurality of conductive lines can be combined and a slit can be provided outside them.

  In the present invention, the resin film may have a flat portion that does not protrude in the thickness direction, and the flat portion may have the slit.

  Therefore, according to the present invention, it is possible to prevent the lowering of the conductivity and the breakage due to the elongation of the conductive wire even in the flat portion.

  The slits of the present invention can be arranged in a line of broken lines.

  By arranging the slits in a line of broken lines, it is possible to obtain a circuit sheet that does not have a decrease in electrical conductivity or breakage.

  The slit of the present invention can be configured to be disposed on one side of the conductive wire.

  Since the stretch in the stretching direction of the resin film can be absorbed by the slit opening on the side where the slit is formed adjacent to the conductive wire, the stretch of the conductive wire in the intersecting direction can be suppressed.

  The slit according to the present invention can be arranged on both sides of the conductive wire.

  According to this, since the elongation in the stretching direction of the resin film can be absorbed by the opening of the slits arranged on both sides of the conductive wire, the elongation of the conductive wire in the intersecting direction can be suppressed.

  The slits of the present invention can be arranged in a plurality of rows on one side of the conductive wire.

  Since there are a plurality of rows of slits on one side of the conductive wires, the extension of the conductive wires in the crossing direction can be suppressed in a multistage manner by the plurality of slits.

  The slits of the present invention can be arranged in a plurality of rows on both sides of the conductive wire.

  Since there are a plurality of rows of slits on both sides of the conductive line, the extension in the intersecting direction on both sides of the conductive line can be suppressed in a multistage manner by the plurality of slits.

  The plurality of slits of the present invention are arranged in parallel, and can be configured to alternately arrange adjacent slits.

  By arranging them alternately, there is no place to pull the conductive wire directly on the resin film, and it is possible to more reliably absorb the extension of the conductive wire in the crossing direction due to the extension in the stretching direction of the resin film by opening the slit. it can.

  The slits arranged near the boundary between the flat part and the three-dimensionally shaped part can be configured such that the length of the slits is longer than that of the other slits, or the interval between the slits is shortened.

  In the vicinity of the boundary between the flat portion and the three-dimensional shape portion of the resin film, the resin film is easily stretched. However, according to the present invention, it is possible to suppress the elongation of the conductive wire at the boundary portion where such a decrease in conductivity or breakage easily occurs due to the slit.

  The length of the slit provided in a portion having a large curvature is longer than the slit provided in a portion having a small curvature in the three-dimensional shape portion of the resin film, or the interval between the slits can be shortened.

  The resin film is easily stretched at the boundary portion where the continuous surface changes in the three-dimensional shape portion of the resin film, for example, at the boundary portion where the curvature of the curved surface changes. However, according to the present invention, it is possible to suppress the elongation of the conductive wire at the boundary portion where such a decrease in conductivity or breakage easily occurs due to the slit.

  The said invention can be comprised so that it may be set as the circuit sheet whose length of one slit is 10 mm or less.

  Since the length per slit is 10 mm or less, each slit opens small with a short length, so that the conductive wire corresponds to the elongation in the stretching direction according to the part of the resin film with a small opening for each slit. Elongation can be suppressed. In addition, when the slit is long, it opens widely and a large deformation occurs in the resin film. However, the present invention can prevent such inconvenience.

  The present invention is made of a material that is more extensible than a resin film, and can be configured to provide a protective layer that covers the slit.

  Since it is made of a material that is more extensible than the resin film and is provided with a protective layer that covers the slit, it is possible to suppress a decrease in the strength of the resin film due to the formation of the slit, and to prevent water leakage through the slit.

  The present invention can be configured such that the conductive coating film is a circuit sheet made of a conductive material in which conductive particles are dispersed in a resin binder.

  Since the conductive coating film is a circuit sheet made of a conductive material in which conductive particles are dispersed in a resin binder, it is possible to obtain a circuit sheet in which a decrease in conductivity and disconnection are unlikely to occur. That is, by the three-dimensional molding, the conductive particles in the binder become sparse in the direction along the conductive lines, but the conductive particles become dense in the crossing direction of the conductive lines. Can keep.

  According to the circuit sheet of the present invention, the elongation of the conductive wire can be suppressed while having a three-dimensionally shaped portion, so that it is possible to make it difficult for the circuit conductivity to be lowered or broken. Therefore, circuit sheets suitable for various three-dimensional products can be realized. Accordingly, the circuit sheet of the present invention can be provided as a circuit sheet for a three-dimensional operation device such as a three-dimensional touch panel.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the circuit sheet by one Embodiment of this invention, A divided drawing (A) is a top view, A divided drawing (B) is a right view of a divided drawing (A). It is the elements on larger scale of the circuit sheet by the modification 1, A divided drawing (A) is an enlarged plan view, A divided drawing (B) is a modification of a divided drawing (A). The partial enlarged plan view of the circuit sheet by the modification 2. FIG. FIG. 10 is a partial enlarged plan view of a circuit sheet according to Modification 3. It is an enlarged plan view of Modification 4 of a part of the circuit sheet. It is an enlarged plan view of Modification 5 of a part of the circuit sheet. It is an enlarged plan view of Modification 6 of a part of the circuit sheet. It is a partial expanded sectional view of the modification 7 of a part of circuit sheet. It is a partial expanded sectional view of the modification 8 of a part of circuit sheet. It is explanatory drawing of the circuit sheet by the modification 9, A part (A) is a top view, A part (B) is a right view of part (A). It is explanatory drawing of the circuit sheet by the modification 11, A divided drawing (A) is a top view, A divided drawing (B) is a right view of a divided drawing (A), A divided drawing (C) is before a divided drawing (A). It is a side view. It is explanatory drawing which shows the mode of the elongation of a resin film and a conductive wire.

  Embodiments of the present invention will be described with reference to the drawings. Note that, in various modified examples, the description of the overlapping portions of common materials, manufacturing methods, effects, and the like is omitted.

  The circuit sheet 11 of the present embodiment is a three-dimensional (three-dimensional) circuit sheet having a circuit 13 made of a conductive coating film on the resin film 12, and the resin film 12 along the conductive wires 14 constituting the circuit 13. A plurality of slits 15 penetrating therethrough are provided.

  The resin film 12 of the circuit sheet 11 shown in FIG. 1 has a rectangular shape in the plan view of FIG. 1A, and gently curves in a dome shape in the lateral direction Y in the right side view of FIG. Is formed. Accordingly, the circuit sheet 11 is formed as a three-dimensional shape portion 12 a that protrudes in the thickness direction Z of the resin film 12 as a whole. This three-dimensional shape part 12a can be made into the shape along the shape of the outer surface or back surface of the housing | casing of the electronic device to accommodate.

  FIG. 1 illustrates a portion in which eight conductive lines 14 are arranged to form a circuit 13, and each slit 15 has a length direction along a direction (length direction) in which the conductive lines 14 extend. ing. In addition, the slits 15 are arranged in a line of broken lines along both sides of the circuit 13. The plurality of slits 15 connected in a row of broken lines are referred to as slit lines 16.

  The length of each slit 15 depends on the size of the resin film 12, but is preferably 10 mm or less in the circuit sheet 11 (or resin film 12) having a size of 150 mm × 200 mm. If it is formed longer than 10 mm, the opening of the slit 15 becomes too large when the resin film 12 is stretched by three-dimensional molding. The length of the slit 15 depends on the thickness of the resin film 12, but is preferably 1 mm or more when the thickness is about 10 μm to 200 μm. This is because the opening when the resin film 12 is stretched is less than 1 mm.

  Further, the distance between the slits 15 arranged in a broken line is preferably 10 mm or less. If it exceeds 10 mm, this portion of the conductive wire 14 may be extended in the width direction and the conductivity may be lowered. The shape of each slit 15 can be linear or curved. The width of the slit 15 can be a slit having no width just by making a cut with a blade, or a slit having a width such as a rectangle or an ellipse using a punching die or the like.

  A thermoplastic resin film can be used for the resin film 11. For example, polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, polycarbonate (PC) resin, polyimide (PI) resin, methacryl (PMMA) resin, polypropylene (PP) resin, polyurethane (PU) resin, polyamide ( It can be formed from PA) resin, polyethersulfone (PES) resin, polyetheretherketone (PEEK) resin, triacetylcellulose (TAC) resin, cycloolefin polymer (COP) and the like.

  As the resin film 11, a primer layer that improves adhesion with a conductive polymer, a surface protective layer, an overcoat layer for the purpose of preventing static charge, or the like that has been subjected to a surface treatment made of an organic polymer is used. May be. Such a resin film 11 may be an integrally molded product that is superimposed on another resin molded body by two-color molding or insert molding.

  The thickness of the resin film 11 is preferably 10 to 200 μm, and more preferably 75 to 125 μm. If the thickness is up to 200 μm, the strength as the circuit sheet 10 is satisfactory, and there is a need to increase the strength as the thickness exceeds 200 μm, and the space in the thickness direction is reduced. On the other hand, if it is less than 10 μm, the durability as a substrate may be insufficient.

  The circuit 13 can be formed using a metal foil such as copper foil or a conductive polymer, but is preferably formed using a conductive paint in which conductive particles are dispersed in a resin binder. Since the conductive particles are included, the conductive particles are densely packed in the direction in which the conductive lines 14 contract, and the conductivity of the conductive lines 14 can be increased.

  As the conductive particles, carbon particles or metal particles can be used, and specific examples include silver, copper, aluminum, nickel, alloys thereof, or particles obtained by coating a metal with silver or gold. . Among these, silver particles having high conductivity and weather resistance are preferably used.

  As the resin binder, an organic polymer can be used. Specific examples include various resins such as acrylic, epoxy, polyester, polyurethane, phenol resin, melamine resin, silicone, polyamide, polyimide, and polyvinyl chloride. Among these, polyester is preferable.

  The circuit sheet 11 is formed by forming a conductive coating film on the resin film 12 by using a printing method such as screen printing on the portion that becomes the circuit 13. This conductive coating film becomes the circuit 10 having the conductive wires 14. Next, slits 15 are formed through the resin film 12 and then formed into a three-dimensional shape by press molding or the like. In this way, the circuit sheet 11 having the three-dimensional shape portion 12a is obtained. As a forming method, in addition to press forming, vacuum forming or pressure forming can also be used. However, since air leaks when the slit 15 is opened in the circuit sheet 11, it is preferable to form a flexible protective film or the like on the circuit sheet 11 and prevent the air leakage from the slit 15. The protective film can be peeled off after molding.

  In the conventional circuit sheet, when the resin film 12 is stretched as shown in FIG. 1 during three-dimensional molding, the conductive wire is also stretched. That is, when the resin film 12 is three-dimensionally formed in a dome shape as shown in FIG. 1, the resin film 12 extends with the thickness direction Z and the short direction Y as stretching directions. For this reason, the conductive wire 14 is similarly stretched, and the conductive particles contained in the conductive wire 14 spread thinly and the density thereof becomes sparse, so that the electrical conductivity is likely to be lowered and an electrical disconnection may occur.

  However, in the circuit sheet 11 of this embodiment, even when the resin film 12 is stretched in the stretching direction (thickness direction Z and short direction Y), the conductive wire 14 has slits 15 as shown in a partially enlarged view in FIG. The elongation of the resin film 12 is suppressed in the opening direction (cross direction of the conductive wires 14). And since the resin film 12 is extended in the direction along the slit 15, the resin film 12 will shrink in the direction in which the slit 15 is opened. As a result, compared to the case where the slits 15 are not provided and the slits 15 are extended in all directions, the thickness of the conductive wires 14 and the density of the conductive particles in the conductive wires 14 are reduced. Can keep sex.

  The circuit sheet 11 as described above can be implemented in various modifications. Although an example of the circuit 13 is shown in FIG. 1, the arrangement, shape, and the like of the slits 15 can be changed as appropriate according to the arrangement, number, shape, and the like of the conductive wires 14 that constitute the circuit 13. Next, a modified example will be described.

Modification 1 [FIG. 2]
A part of the circuit sheet 11 in which no other conductive line exists in the vicinity of one conductive line 14 is shown in FIG. In such a portion, slit lines 16 and 16 can be provided on both sides of the conductive wire 14. As shown in FIG. 2A, the slit lines 16, 16 can be provided symmetrically with respect to the conductive line 14 (see, for example, the P1 portion in FIG. 2A). However, as shown in FIG. 2B, they can be provided alternately (see, for example, the P2 portion in FIG. 2B). This is because the staggered arrangement can make up the portion of the slit line 16 on the one side without the slit 15 with the slit 15 of the slit line 16 on the other side.

Modification 2 [FIG. 3]
An example in which a plurality of slit lines 16, 16 are provided on one side of one conductive wire 14 is shown in FIG. Even if the slit 15 in one slit line 16 is not enough to absorb the elongation in the stretching direction of the resin film 12, it can be compensated by opening the slit 15 in the other slit line 16. . In other words, since many slits 15 can be opened in the direction intersecting the conductive line 14, the conductive line 14 is not easily extended in the direction intersecting the conductive line 14.

  The slit lines 16 and 16 on one side of the conductive wire 14 are preferably provided alternately. This is because the staggered arrangement can supplement the portion of the slit line 16 on the one side without the slit 15 with the slit 15 on the slit line 16 on the other side. Further, in the slit lines 16 and 16, the slits 15 may be provided alternately and overlap each other. This is because even if the opening of each slit 15 is small, it can be opened largely as a whole.

Modification 3 [FIG. 4]
As shown in FIG. 4, even when the conductive line 14 includes a curve, the slit line 16 having the slit 15 along the curve can be provided. Further, when the slit 15 cannot be provided on both sides of the conductive wire 14, the slit wire 16 may be provided on one side of the conductive wire 14.

Modification 4 [FIG. 5]
For a portion as shown in FIG. 5 in which a plurality of conductive lines 14 form a circuit 13 in parallel, slits cannot be provided on both sides of each conductive line 14, so a slit is formed on one side of the circuit 13. A line 16 can be provided.

Modification 5 [FIG. 6]
The size and interval of the slits 15 included in one conductive wire 14 can be appropriately changed depending on the shape of the conductive wire 14 and the resin film 12. For example, the length of the slit 15 can be made longer in a portion where the conductive wire 14 is bent than in a straight portion, and in a portion where the curvature is large, compared to a portion where the curvature is small. In the example shown in FIG. 6, the length of the slit 15a at the bent portion of the conductive wire 14 is long, and the length of the slit 15b at the straight portion of the conductive wire 14 is short.

Modification 6 [FIG. 7]
In the modified example 6, for example, the interval between the slits 15 can be shortened in a portion where the conductive wire 14 is bent compared to a straight portion, and in a portion where the curvature is large compared to a portion where the curvature is small. In the example shown in FIG. 7, the interval between the slits 15 c at the bent portion of the conductive wire 14 is short, and the interval between the slits 15 d at the straight portion of the conductive wire 14 is long.

Modification 7 [FIG. 8]
FIG. 8 is a partial enlarged cross-sectional view of the circuit sheet 11 at the slit line 16 portion, unlike the previous drawings. The slit 15e disposed in the vicinity of the boundary between the flat portion 12b of the resin film 12 and the three-dimensional shape portion 12a that three-dimensionally protrudes and deforms can be made longer than the slit 15f disposed elsewhere. Further, the interval between the slits 15e can be made shorter than the interval between the slits 15f. That is, both side portions of the bent portion 12c rising in a three-dimensional shape correspond to the increase in the elongation of the resin film 12.

Modification 8 [FIG. 9]
As shown in FIG. 9, the length of the slit 15g provided in the portion 12d having a large curvature in the three-dimensional shape portion 12a of the resin film 12 may be made longer than the length of the slit 15h provided in the portion 12e having a small curvature. it can. Further, the interval between the slits 15g can be made shorter than the interval between the slits 15h. Also in this case, it is made to respond | correspond to the elongation of the resin film 12 becoming large in the location where a three-dimensional shape change is large.

Modification 9 [FIG. 10]
FIG. 10 shows a modification of the resin film 12 of the circuit sheet 11. The resin film 12 in FIG. 1 shows an example in which the entire lateral direction Y is gently curved in a dome shape, but the resin film 12 in FIG. 10 is small on both sides of a three-dimensional shape portion 12a that is curved in a dome shape. This is an example in which a flat portion 12b is formed. The conductive wire 14 is formed across the three-dimensional shape portion 12a and the flat portion 12b. Even if the resin film 12 is formed in such a shape that the three-dimensionally shaped portion 12a and the flat portion 12b are combined, and the conductive wire 14 is formed so as to straddle them, the resin film 12 is stretched by forming the slit 15 Can be absorbed, and the elongation of the conductive wire 14 can be suppressed.

Modification 10
About the circuit sheet 11 of the said embodiment, you may make it provide a protective layer. The protective layer only needs to be large enough to cover the slit 15. Therefore, an independent protective layer can be provided for each slit 15. Further, another layer as a protective layer can be laminated on the entire resin film 12. The protective layer is preferably made of a paint film material or a rubber film that can be easily stretched so that the slit 15 can be opened. By providing the protective layer, insulation protection of the circuit 13 and passage of dust, moisture, and the like through the slit 15 can be prevented.

Modification 11 [FIG. 11]
FIG. 11 shows a modification of the resin film 12 of the circuit sheet 11. The resin film 12 in FIG. 1 shows an example in which the entire short direction Y is gently curved in a dome shape, but the resin film 12 in FIG. This is an example in which a three-dimensionally shaped portion 12a that is gently curved into a dome shape is formed. 11B and 11C, the conductive lines 14 and the slits 15 are not shown, but the conductive lines 14 and the slits 15 in FIG. 11A are actually provided. By forming the slit 15, the stretching of the resin film 12 can be absorbed and the elongation of the conductive wire 14 can be suppressed.

  The above embodiment is an example of the present invention, and the present invention is not limited to such a form. The shape, material, manufacturing method, and the like of each member can be changed or replaced within the scope not departing from the gist of the present invention. is there. For example, the slit 15 is formed in the shape of a broken line. However, this should not be interpreted in a limited manner, and includes a long line, a perforated line, a dotted line, and the like.

DESCRIPTION OF SYMBOLS 1 Resin film 2 Conductive wire 11 Circuit sheet 12 Resin film 12a Three-dimensional shape part 12b Flat part 12c Bending part (boundary)
12d Location with a large curvature 12e Location with a small curvature 13 Circuit 14 Conductive lines 15, 15a, 15b, 15c, 15d, 15e, 15f, 15g, 15h Slit 16 Slit line P1, P2 region

Claims (11)

In a circuit sheet having a circuit in which conductive wires of a conductive coating film are formed on a resin film,
The resin film has a three-dimensional shape part protruding in the thickness direction,
The solid portion has a plurality of slits formed along the conductive lines,
The circuit sheet, wherein the slit is open in the extending direction of the resin film forming the three-dimensional shape portion.
The circuit sheet according to claim 1, wherein the resin film has a flat portion that does not protrude in the thickness direction, and the flat portion also has the plurality of slits.
The circuit sheet according to claim 1, wherein the plurality of slits are arranged in a line of a broken line.
The circuit sheet according to claim 1, wherein the plurality of slits are arranged on both sides of the conductive wire.
The circuit sheet according to claim 1, wherein the plurality of slits are arranged in a plurality of rows only on one side of the conductive wire.
The plurality of slits are arranged in parallel;
The circuit sheet according to any one of claims 1 to 5, wherein adjacent slits are alternately arranged.
7. The slit according to any one of claims 1 to 6, wherein the slit disposed near the boundary between the flat portion and the three-dimensional shape portion has a longer slit length or a shorter interval between slits than other slits disposed. The circuit sheet according to 1.
The length of the slit provided in the location with a large curvature compared with the slit provided in the location with a small curvature among the three-dimensional shape parts of the said resin film is long, or the space | interval of slits is short in any one of Claims 1-6. The circuit sheet as described.
The length of one slit is 10 mm or less, The circuit sheet in any one of Claims 1-8.
The circuit sheet according to any one of claims 1 to 9, further comprising a protective layer made of a material that is more extensible than the resin film and covering the slit.
  The circuit sheet according to any one of claims 1 to 10, wherein the conductive coating film is made of a conductive material in which conductive particles are dispersed in a resin binder.

Images