Injection molded product and method for manufacturing the same

Abstract

The present invention provides an injection molded product, the purpose of which is to form a sealing material on a through-hole, thereby suppressing the sealing material from flowing through the conductive material filled in the through-hole by heat and resin pressure during resin injection, thereby preventing the conductive layers formed on both sides of the base sheet from being broken. The injection molded product (10) is in the shape of a flat rectangular parallelepiped, and comprises a flat molded resin body (11) composed of injection molding resin and a base sheet (40) fixed to the surface of the molded resin body (11). The base sheet (40) has a first conductive layer (44) and a through-hole (43) extending from the first side (41) to the second side (42) formed on the first side (41). The through-hole (43) is filled with conductive material, and a second conductive layer (45) is formed in a manner electrically connected to the first conductive layer (44) via the filled conductive material. In addition, a sealing material (46) is formed on the first conductive layer (44) in a manner covering the through-hole (43). The molded resin body (11) is fixed to the first surface (41) side of the base sheet (40) in a manner covering the sealing material (46).

Description

Technical Field

[0001] The present invention relates to an injection molded product (injection molded product) including a base sheet having a conductive layer and through holes, and a method for manufacturing the same. Background Art

[0002] There are injection-molded products in which a base sheet with conductive layers formed on both sides is fixed to the surface. The conductive layers are electrically connected via conductive material filled in through-holes extending through the base sheet. For example, Patent Document 1 discloses a printed wiring board molded body in which a base sheet with circuit patterns formed on both sides is integrated with a molding resin. The circuit patterns are electrically connected via a copper plating layer formed in the through-holes extending through the base sheet. To prevent the conduction of the through-holes from being destroyed by heat and resin pressure during resin injection, this printed wiring board molded body has a cover film formed on the surface of the base sheet that is bonded to the injected resin.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 7-142817

[0006] Because conventional printed wiring board molded bodies utilize a coverlay film, they cannot be formed locally on the through-holes associated with the conduction between the two sides of the substrate. Instead, the coverlay film must be formed over the entire surface of the base sheet. Furthermore, during molding, if there are other layers between the coverlay film and the base sheet, bubbles and wrinkles may form in these layers, making this method unsuitable for three-dimensional molded bodies. Summary of the Invention

[0007] The present invention is completed to solve the above-mentioned problems. Its purpose is to suppress the flow of conductive material filled in the through hole by heat and resin pressure during resin injection without using a covering film covering the entire surface of the base sheet, thereby preventing disconnection between conductive layers.

[0008] In order to achieve the above-mentioned purpose, the first invention is an injection-molded product, which comprises: a base sheet, in which a first conductive layer is formed on a first surface, and a second conductive layer electrically connected to the first conductive layer via a conductive material filled in a through hole extending from the first surface to the second surface is formed on the second surface; a sealing material, wherein the sealing material is formed at least on the first conductive layer in a manner covering the through hole; and a molded resin body, wherein the molded resin body is formed on the base sheet in a manner covering the sealing material and is composed of an injection-molded resin.

[0009] A second invention is an injection-molded article according to the first invention, wherein the sealing material protrudes toward the through hole.

[0010] According to this structure, since the injection molding resin does not flow through the conductive material in the through hole, disconnection between the first conductive layer and the second conductive layer can be prevented.

[0011] A third invention is an injection-molded article according to the first invention or the second invention, wherein the sealing material is formed so as to extend from above the first conductive layer to above the first surface of the base sheet.

[0012] According to this structure, the sealing material is fixed to the base sheet in addition to the first conductive layer, so that the sealing material can be less likely to flow due to the injection molding resin.

[0013] A fourth invention is an injection molded article according to any one of the first to third inventions, wherein the sealing material is made of the same material as the conductive material.

[0014] According to this structure, the sealing material that has intruded into the through hole becomes a conductive material, and thus it is possible to more reliably prevent the resistance value of the conductive portion between the first conductive layer and the second conductive layer from increasing.

[0015] A fifth invention is an injection molded article according to any one of the first to fourth inventions, wherein the second conductive layer is a conductive adhesive, and further includes a flexible printed wiring board fixed so as to be electrically connected to the conductive adhesive.

[0016] According to this structure, since it is not necessary to provide terminals for connection with a flexible printed wiring board, the material of the injection molded product can be reduced and the structure can be simplified.

[0017] The sixth invention is an injection-molded product, which, in any one of the first to fourth inventions, further comprises a first detection electrode formed on the first surface, wherein the first detection electrode is electrically connected to the first conductive layer to detect the touch input position, the first conductive layer is a first wiring (routing wiring) that transmits a signal detected by the first detection electrode, and the second conductive layer is a second wiring that further transmits the signal transmitted from the first wiring via the conductive material.

[0018] With this structure, even in a touch panel in which wiring is drawn from the first surface to the second surface through a through hole, the injection molding resin does not flow through the conductive material in the through hole, thereby preventing disconnection of the first wiring and the second wiring.

[0019] The seventh invention is a method for manufacturing an injection-molded product, which comprises the following steps: a step of arranging a base sheet in a cavity of an injection molding mold in a manner such that the second surface contacts the cavity surface, in the base sheet, a first conductive layer is formed on the first surface, a second conductive layer electrically connected to the first conductive layer via a conductive material filled in a through-hole extending from the first surface to the second surface is formed on the second surface, and a sealing material is formed at least on the first conductive layer in a manner covering the through-hole; a step of injecting molten resin into the cavity and filling the cavity in a manner such that the conductive material does not flow; and a step of cooling the molten resin and solidifying it to form a molded resin body, while fixing the base sheet to the surface of the molded resin body.

[0020] According to this structure, since the molten resin is suppressed from intruding into the through hole through the sealing material, an injection molded product in which the first conductive layer and the second conductive layer are electrically connected can be manufactured.

[0021] Effects of the Invention

[0022] According to the present invention, an injection-molded product can be obtained in which disconnection of the first conductive layer and the second conductive layer is prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic cross-sectional view of an injection-molded product according to the first embodiment of the present invention.

[0024] Figure 2 yes Figure 1 This is an enlarged view of section A of the injection-molded part shown.

[0025] Figure 3 yes Figure 1 A top view of section A of the injection-molded product shown.

[0026] Figure 4 This is a schematic cross-sectional view of a base sheet used for the injection-molded article according to the first embodiment of the present invention.

[0027] Figure 5 yes Figure 4 An enlarged view of part B of the base sheet is shown.

[0028] Figure 6 yes Figure 4 A top view of portion B of the base sheet is shown.

[0029] Figure 7 Yes Figure 1 Schematic cross-sectional view of the manufacturing process of the injection molded product shown.

[0030] Figure 8 This is a modified example of the base sheet of the present invention. Figure 5 Corresponding enlarged view of part C.

[0031] Figure 9 This is a modified example of the base sheet of the present invention. Figure 6 Corresponding top view of part C.

[0032] Figure 10 This is a schematic cross-sectional view of a base sheet used for an injection-molded article according to a second embodiment of the present invention.

[0033] Figure 11 This is a schematic cross-sectional view of a base sheet used for an injection-molded article according to a third embodiment of the present invention.

[0034] Explanation of symbols

[0035] 10, 10A, 20, 30 Three-dimensional molded products with circuits

[0036] 11, 11A, 21, 31 Molded resin body

[0037] 40, 40A, 50, 60 substrate sheets

[0038] 41, 41A, 51, 61 Page 1

[0039] 42, 42A, 52, 62, page 2

[0040] 43, 43A, 53, 63 through holes

[0041] 44, 44A, 54, 64 first conductive layer

[0042] 45, 45A, 55, 65 second conductive layer

[0043] 46, 46A, 56, 66 sealing materials

[0044] 57 Conductive Adhesive

[0045] 58 Flexible printed wiring board

[0046] 71 first detection electrode

[0047] 73 First Wiring

[0048] 74 Second wiring

[0049] 83 Cavity

[0050] 84 Cavity surface DETAILED DESCRIPTION

[0051] Next, refer to the attached Figure 1 Embodiments of the present invention will be described.

[0052] Reference Figure 1The injection molded article 10 according to the first embodiment of the present invention is in the shape of a flat rectangular parallelepiped and includes a flat molded resin body 11 made of injection molded resin and a base sheet 40 fixed to the surface of the molded resin body 11. The base sheet 40 has a first conductive layer 44 extending in a strip shape to the left and right and a through hole 43 extending from the first surface 41 to the second surface 42 formed on the first surface 41. The through hole 43 is filled with a conductive material, and a second conductive layer 45 extending in a strip shape to the left and right is formed on the second surface 42 so as to be electrically connected to the first conductive layer 44 via the filled conductive material. In addition, a sealing material 46 is formed on the first conductive layer 44 so as to cover the through hole 43. Here, covering the through hole 43 means not only completely covering the through hole 43 with the sealing material 46, but also partially covering the through hole 43 with the sealing material 46, leaving a portion of the through hole 43 exposed. The molded resin body 11 is fixed to the first surface 41 side of the base sheet 40 so as to cover the sealing material 46.

[0053] In other words, in the injection-molded article 10, the base sheet 40 has: a through-hole 43 extending from the first surface 41 to the second surface 42 and filled with a conductive material; a first conductive layer 44 formed on the first surface 41 at a position overlapping at least the opening of the through-hole 43 when viewed from above; a sealing material 46 formed on the first conductive layer 44 at a position overlapping at least the opening of the through-hole 43 when viewed from above; and a second conductive layer 45 formed at a position overlapping at least the opening of the through-hole 43 when viewed from above in a manner electrically connected to the first conductive layer 44 by the conductive material filled in the through-hole 43, and the molded resin body 11 is provided on the first surface of the base sheet 40.

[0054] The "conductive material filling the through-hole" used in the present invention is not limited to completely filling the through-hole 43. As long as the first conductive layer 44 and the second conductive layer 45 can be electrically connected, the conductive material can also be formed only on the wall surface of the through-hole 43, leaving the through-hole 43 hollow. Even if the through-hole 43 is hollow, the conductive material in the through-hole 43 can be protected by the sealing material 46 from the injection pressure during the formation of the molded resin body 11, thereby preventing the first conductive layer 44 and the second conductive layer 45 from disconnecting. However, when the through-hole 43 is completely filled with the conductive material, the conductive material is less likely to be squeezed out by the injection pressure, which is preferable.

[0055] Reference Figure 2 , the detailed shape of the sealing material 46 will be described. Figure 2 yes Figure 1FIG4 is an enlarged view of section A indicated by the dotted line. The injection pressure of the molded resin body 11 causes the sealing material 46 to protrude from above the first conductive layer 44 toward the through-hole 43, and a portion of the sealing material 46 penetrates the through-hole 43. Although the first conductive layer 44 has a hole through which the sealing material 46 penetrates, the first conductive layer 44 is in contact with the conductive material in the through-hole 43, so the first conductive layer 44 and the second conductive layer 45 are not disconnected. Figure 3 This is a top view of an enlarged portion A viewed from the first surface 41 of the base sheet 40. The molded resin body 11 is omitted, and the through-hole 43, hidden by the sealant 46, and the second conductive layer 45 formed on the second surface 42 are indicated by dashed lines. The first conductive layer 44 and the second conductive layer 45 are circularly shaped on the through-hole 43, covering the opening of the through-hole 43. The first conductive layer 44 extends leftward from the through-hole 43, while the second conductive layer 45 extends rightward from the through-hole 43 in opposite directions. The area of ​​the through-hole 43 opening, the bottom surface of the first conductive layer 44 above the through-hole opening, and the bottom surface of the sealant 46 are in the order of through-hole 43 < sealant 46 < first conductive layer 44. By simply forming the sealant 46 to a size sufficient to cover the opening of the through-hole 43, the injection pressure during molding of the molded body 11 can be mitigated. Furthermore, the bottom surface area of ​​the sealant 46 is preferably 1.2 to 2 times the area of ​​the through-hole 43 opening. If it is larger than 1.2 times, sufficient protection can be provided from the injection pressure, and if it is smaller than 2 times, it is a size that can effectively provide protection from the injection pressure while reducing waste of material.

[0056] The first conductive layer 44 is, for example, an electrode or wiring for a touch panel, a heater, a thermistor, an LED, or a wireless communication transceiver antenna. The second conductive layer 45 is formed to take the electrical signal of the first conductive layer 44 from the first surface 41 to the second surface 42 through the through hole 43. By integrating the base sheet 40 having the first conductive layer 44 and the second conductive layer 45 with the molded resin body 11, it can be used as a housing having functions such as a touch panel, a heater, a thermistor, an LED, and a wireless communication transceiver antenna corresponding to the functions of the first conductive layer 44. The second conductive layer 45 is taken out to the outside of the injection molded product 10 through a terminal (not shown) and is connected to a control substrate that controls functions such as the touch panel, heater, thermistor, LED, and wireless communication transceiver antenna. The terminal is, for example, a flexible printed wiring board (FPC) or a contact pin. The contact pin is a cylindrical component made of a conductive material. A control substrate including contact pins is disposed below the second conductive layer 45 , and the contact pins are fixed to the second conductive layer 45 via a conductive adhesive, thereby connecting the second conductive layer 45 and the control substrate.

[0057] The base sheet 40 may be made of thermoplastic resins such as polypropylene resin, polyethylene resin, polyamide resin, acrylic resin, olefin resin, epoxy resin, polyimide resin, thermoplastic polyurethane, silicone resin, polyester resin, vinyl chloride resin, polycarbonate resin, ABS resin, or laminates thereof, for example. The base sheet 40 preferably has a thickness of 12 μm to 200 μm, for example. A base sheet 40 with a thickness of 12 μm or greater provides excellent handleability, while a thickness of 200 μm or less provides adequate rigidity and thus good flexibility.

[0058] The materials constituting the first conductive layer 44 and the second conductive layer 45, and the conductive materials filled in the through-holes 43, include, for example, metals such as gold, platinum, silver, copper, aluminum, nickel, zinc, and lead; metal oxides such as ITO, ZnO, IGO, IGZO, and CuO; conductive polymers such as PEDOT (polyethylenedioxythiophene) and PSS (polystyrene sulfonate); and carbon materials such as carbon nanotubes, graphite, and graphene. The materials described above can also be used as pastes or nanofibers. Among these materials, silver paste is particularly preferred. Because silver paste is easily elongated, it is less likely to break even if the base sheet 40 is deformed during handling. Furthermore, the conductive materials filled in the first conductive layer 44, the second conductive layer 45, and the through-holes 43 may be the same material or different materials.

[0059] The thickness of the first conductive layer 44 and the second conductive layer 45 is preferably 1 μm to 15 μm, for example. When the thickness of the first conductive layer 44 and the second conductive layer 45 is 1 μm or greater, the conductive layer is less likely to break. When the thickness is 15 μm or less, the conductive layer has good flexibility and is less likely to break even if the base sheet 40 is deformed during handling.

[0060] The material constituting the sealing material 46 can be selected from the materials listed as the conductive materials filled in the first conductive layer 44, the second conductive layer 45 and the through-hole 43. Among these materials, it is preferably composed of the same material as the conductive material filled in the through-hole 43. If it is composed of the same material as the conductive material filled in the through-hole 43, since the sealing material 46 that invades the through-hole 43 becomes a conductive material, it is possible to more reliably prevent the resistance value of the conductive portion between the first conductive layer 44 and the second conductive layer from becoming higher. In addition, a conductive polymer with ductility (materials listed in the first conductive layer, carbon ink, etc.) can also be used. Furthermore, a resin material can also be used to form the sealing material 46. As the resin material, for example, ultraviolet curing resin and two-liquid curing resin are used. Acrylate-based and epoxy-based resins can be used as ultraviolet curing resins. In addition, among the two-liquid curing resins, polyurethane-based, silicon-based, epoxy-based, and acrylic-based resins are used.

[0061] The thickness of sealing material 46 is preferably 2 μm to 500 μm. A thickness of 2 μm or greater can more effectively protect the conductive material filling through-hole 43 from the injection pressure during formation of molded resin body 11. A thickness of 500 μm or less can reduce waste of material used to form sealing material 46 and prevent the conductive material filling through-hole 43 from flowing. Sealing material 46 can be formed on first conductive layer 44 using a dispenser, for example.

[0062] The molded resin body 11 may be, for example, a general-purpose resin such as polystyrene resin, polyolefin resin, ABS resin, AS resin, or AN resin; a general-purpose engineering resin such as polycarbonate resin, acrylic resin, or thermoplastic polyurethane; or a super-engineering resin such as a polyimide resin or liquid crystal polyester resin. Alternatively, a composite resin containing reinforcing materials such as glass fiber or inorganic fillers may be used. The thickness of the molded resin body 11 is not particularly limited and is selected based on the thickness of the housing of the product being manufactured.

[0063] Next, refer to Figure 4 The base sheet 40 before the molded resin body 11 is fixed has the same shape as the base sheet 40 except for the shape of the sealing material 46. Figure 1 The same is true of the base sheet 40 shown in the state of being fixed to the molded resin body 11 of the injection molded product 10. In addition, the molded resin body 11 formed by injection molding later is shown by the double-dashed line. Figure 5 , the detailed shape of the sealing material 46 will be described. Figure 5 yes Figure 4 The enlarged view of the B portion shown by the dotted line. The sealing material 46 and Figure 2 The shape of the sealing material 46 after injection molding is different. It is formed into a hemispherical shape that is convex on the side opposite to the through hole 43 on the first conductive layer 44. In the process of forming and fixing the molded resin body 11 on the first surface 41 side of the base sheet 40 by injection molding, as shown in FIG. Figure 2 As shown, the sealing material 46 is deformed into a shape protruding toward the through hole 43 by the injection pressure. Figure 6 The expanded portion B is viewed from the first surface side 41 of the base sheet 40. The positional relationship among the first conductive layer 44, the second conductive layer 45, and the sealing material 46 is shown after being fixed to the molded resin body 11. Figure 3 The positional relationship shown is the same.

[0064] Next, a method for manufacturing the injection-molded article 10 will be described.

[0065] A base sheet 40 is prepared, wherein the base sheet 40 has a first conductive layer 44 formed on a first surface 41, a through hole 43 extending from the first surface 41 to the second surface 42, a second conductive layer 45 electrically connected to the first conductive layer 44 via a conductive material filled in the through hole 43 is formed on the second surface 42, and a sealing material 46 is formed on the first conductive layer 44 in a manner covering the through hole 43.

[0066] Next, refer to Figure 7 (a) An injection molding die consisting of a first die 80 having a resin injection port 82 and a second die 81 having a recessed portion is prepared, and the second surface 42 of the base sheet 40 is placed in contact with the second die 81. Figure 7 (b) The first mold 80 and the second mold 81 are closed. The space formed by closing the first mold 80 and the second mold 81 is called a cavity 83, and the surface of the second mold 81 forming the cavity 83 is called a cavity surface 84. The base sheet 40 is arranged in such a way that the second surface is in contact with the cavity surface 84. Next, molten resin is injected into the cavity 83 from the injection port 82 of the first mold 80. At this time, the sealing material 46 formed on the first conductive layer 44 of the base sheet 40 is suppressed from flowing through the conductive material in the through hole 43 due to the injection pressure of the molten resin, and the sealing material 46 protrudes toward the through hole 43. Next, by cooling until the molten resin solidifies, a molded resin body 11 is formed.

[0067] In the process of solidifying the molten resin to form the molded resin body 11, the base sheet 40 is fixed to the surface of the molded resin body 11. Figure 7 (c) The injection molding die is opened, and the injection molded product 10 is taken out using a take-out arm (not shown), thereby obtaining the injection molded product 10 .

[0068] As described above, in the injection molded product 10 manufactured as described above, the sealing material 46 prevents the molten resin from entering the through-hole 43 . Therefore, the molten resin does not flow through the conductive material filling the through-hole 43 , and an injection molded product in which the first conductive layer 44 and the second conductive layer 45 are electrically connected can be manufactured.

[0069] Next, with reference to the drawings, a modified example of the present invention will be described, focusing on differences from the previous embodiment.

[0070] The injection molded article 10A as a modified example of the present invention can be obtained using the same materials and the same manufacturing method as the injection molded article 10 shown in the previous embodiment. However, the formation position of the sealing material 46A of the base sheet 40A used in the injection molded article 10A is different. Figure 8 This is an enlarged view of the C portion of the through hole periphery of the base sheet 40A used for the injection molded product 10A. Figure 5 The corresponding figure. Figure 9This is the top view of part C, which is the same as Figure 6 Modifications will be described with reference to these drawings.

[0071] Reference Figure 8 The through hole 43A, the first conductive layer 44A, and the second conductive layer 45A formed in the base sheet 10A are formed in the same manner as the base sheet 10 according to the first embodiment. The sealing material 46A is formed at least on the first conductive layer 44A so as to cover the through hole 43A, which is the same as the base sheet 10 according to the first embodiment, but is further formed from above the first conductive layer 44A across the first surface 41A of the base sheet 10A. Figure 9 The area of ​​the opening of through-hole 43A, the area of ​​the bottom surface of first conductive layer 44A above the opening of through-hole 43A, and the area of ​​sealing material 46A are in the order of through-hole 43A < first conductive layer 44A < sealing material 46A, thereby protecting through-hole 43A with sealing material 46A. With this configuration, when base sheet 10A is placed in an injection molding mold and injection molding resin is injected onto first surface 41A to form molded resin body 11A, sealing material 46A is fixed to first surface 41A of base sheet 40A in addition to first conductive layer 44A. Therefore, sealing material 46A is less likely to flow due to injection molding resin.

[0072] Next, a second embodiment of the present invention will be described with reference to the drawings, focusing on differences from the previous embodiments.

[0073] Reference Figure 10 The injection-molded article 20 is a flat rectangular parallelepiped, and the first surface 51 of the base sheet 50 is fixed to the molded resin body 21 indicated by the two-dot chain line. The manufacturing method of the injection-molded article 20 is the same as that of the injection-molded article 10 shown in the first embodiment. However, the second conductive layer 55 formed on the second surface 52 of the base sheet 50 is different. On the first surface 51 of the base sheet 50, a first conductive layer 54 is formed above a through-hole 53 extending from the first surface to the second surface. A sealing material 56 is formed on the first conductive layer 54 to cover the through-hole 53. The through-hole 53 is filled with a conductive material. On the second surface 52 of the base sheet 50, a conductive adhesive 57 is formed to electrically connect the conductive material through the through-hole 53 to the second conductive layer 54. This conductive adhesive 57 serves as the second conductive layer 55. Furthermore, a flexible printed wiring board 58 is fixed to the second surface 52 of the base sheet 50 so as to be electrically connected to the conductive adhesive 57. The flexible printed wiring board 58 is bent downward and connected to a control board (not shown).

[0074] By placing the base sheet 50 in an injection molding die and forming the molded resin body 21 on the first surface 51, an injection molded article 20 can be obtained. This configuration eliminates the need for terminals for connection to the flexible printed wiring board 58, thereby reducing the material of the injection molded article 20 and simplifying the structure.

[0075] Next, a third embodiment of the present invention will be described with reference to the accompanying drawings, focusing on the differences from the previous embodiments. The injection-molded article 30 is a flat rectangular parallelepiped, and the first surface 61 of the base sheet 60 is fixed to the molded resin body 31 indicated by the two-dot chain line. The manufacturing method for the injection-molded article 30 is the same as that for the injection-molded article 10 shown in the first embodiment. However, the first conductive layer 64 formed on the first surface 61 of the base sheet 60 and the second conductive layer 65 formed on the second surface 62 are different. Furthermore, the injection-molded article 30 can be used as a touch panel.

[0076] Reference Figure 11 A through hole 63 is formed in the base sheet 60, and the through hole 63 is filled with a conductive material. A first detection electrode 71 in the form of a strip extending to the left and right is formed on the first surface 61 of the base sheet 60 where the through hole 63 is not formed. Figure 11 Although only one first detection electrode 71 is visible in the figure, multiple first detection electrodes 71 are actually formed parallel to each other, extending left and right along the front-to-back direction of the cross-section of the base sheet 60. On the second surface 62, in locations where the through-holes 63 are not formed, multiple second detection electrodes 72 are formed perpendicularly and parallel to the multiple first detection electrodes 71. Furthermore, a first wiring 73 is formed across the first surface 61 of the base sheet 60, covering the through-holes 63, to electrically connect to the first detection electrodes 71. This first wiring 73 constitutes the first conductive layer 64. Furthermore, a second wiring 74 is formed on the second surface 62, electrically connected to the first wiring 73 via the conductive material within the through-holes 63, to lead the first wiring 73 to the second surface 62. This second wiring 74 constitutes the second conductive layer 65. Signals indicating the touch input position detected by the first detection electrodes 71 are transmitted via the first wiring 73, led to the second surface 62 via the conductive material filling the through-holes 63, and then transmitted to the second wiring 74. The signal indicating the touch input position detected by the second detection electrode 72 is transmitted via the wiring for the second detection electrode 72 (not shown). The second wiring 74 and the wiring for the second detection electrode 72 (not shown) are connected to the outside of the injection molded article 30 via terminals (not shown) and connected to the control substrate. The terminals are, for example, flexible printed circuit boards (FPCs) or contact pins. The sealing material 66 is formed on the first wiring 73 to cover the through-hole 63.

[0077] By placing the base sheet 60 in an injection molding die and forming the molded resin body 31 on the first surface 61, an injection molded article 30 can be obtained. With this configuration, even in a touch panel where wiring is drawn from the first surface to the second surface via the through-holes 63, the injection molding resin does not flow through the conductive material within the through-holes 63, thereby preventing disconnection of the first wiring 73 and the second wiring 74.

[0078] The first wiring 73 and the second wiring 74 are, for example, metals such as gold, platinum, silver, copper, aluminum, nickel, zinc, and lead; metal oxides such as ITO, ZnO, IGO, IGZO, and CuO; conductive polymers such as PEDOT (polyethylenedioxythiophene) and PSS (polystyrene sulfonic acid); and carbon materials such as carbon nanotubes, graphite, and graphene.

[0079] The thickness of the first wiring 73 and the second wiring 74 is preferably 1 μm to 15 μm, for example. When the thickness of the first wiring 73 and the second wiring 74 is 1 μm or greater, the wiring is less likely to break. When the thickness is 15 μm or less, the wiring has good flexibility and is less likely to break even when the base sheet 60 is deformed during handling.

[0080] Furthermore, in the aforementioned embodiments, a flat injection-molded article is used, and the surface for securing the base sheet is a flat surface. However, the base sheet can also be secured to a curved surface. The base sheet used in the present invention does not use a cover film to protect it from the injection pressure of the molding resin. When the base sheet is molded into a three-dimensional shape, there is no need to consider the formation of bubbles or wrinkles in the cover film or in the layer between the base sheet and the cover film. Therefore, the securing surface is easily applicable to injection-molded articles with curved surfaces.

[0081] In the above-described embodiments, a first conductive layer, a sealing material, and a second conductive layer are formed on the base sheet. However, a protective film may be further formed on the second surface of the base sheet. The step of placing the base sheet so that the second surface of the base sheet contacts the cavity surface includes the case where the second surface of the base sheet contacts the cavity surface via the protective film.

[0082] Furthermore, in each of the above-described embodiments, one through hole is formed in the base sheet, but the number of through holes is not limited to one, and a plurality of through holes may be formed.

[0083] Furthermore, in each of the above-mentioned embodiments, the sealing material protrudes toward the through hole and invades the through hole, but as long as the sealing material is prevented from flowing through the conductive material filled in the through hole due to the injection pressure of the molding resin, it can also be a shape in which the upper part of the sealing material is recessed without invading the through hole, or a hemispherical shape before the upper part of the sealing material is injected into the molding resin without being recessed.

[0084] Furthermore, in each of the above-mentioned embodiments, a structure in which a hole through which the sealing material passes is opened in the first conductive layer is described, but it is also possible that no hole is opened in the first conductive layer, and the first conductive layer is formed into a shape that is recessed toward the through hole due to the pressure of the sealing material pressed by the injection pressure of the molding resin.

[0085] Furthermore, in each of the above-described embodiments, the first surface of the base sheet is directly fixed to the molded resin body. However, an adhesive layer may be formed on the first surface of the base sheet so that the base sheet is fixed to the molded resin body via the adhesive layer.

[0086] Furthermore, in the above-described embodiments, the entire surface of the base sheet is fixed to the molded resin body. However, the base sheet may have a surface that is not bonded to the molded resin body, or the base sheet may extend outside the molded resin body. Alternatively, the second conductive layer may extend outside the molded resin body along with the base sheet, and the portion of the second conductive layer that extends outside the molded resin body may be connected to the control substrate.

Claims

1. An injection molded product, characterized in that have: a base sheet having a first conductive layer formed on a first surface and a second conductive layer formed on a second surface electrically connected to the first conductive layer via a conductive material completely filling a through hole extending from the first surface to the second surface; a sealing material, the sealing material being formed at least on the first conductive layer in a manner of covering the through hole; as well as a molded resin body formed on the base sheet so as to cover the sealing material and made of an injection-molded resin; The injection molding resin does not invade the through-hole.

2. The injection molded article according to claim 1, wherein The sealing material protrudes toward the through hole.

3. The injection molded article according to claim 1 or 2, wherein: The sealing material is formed so as to extend from above the first conductive layer to above the first surface of the base sheet.

4. The injection molded article according to claim 1 or 2, wherein: The sealing material is made of the same material as the conductive material.

5. The injection molded article according to claim 1 or 2, wherein: The second conductive layer is a conductive adhesive, The injection molded product further includes a flexible printed wiring board fixed to the conductive adhesive so as to be electrically connected thereto.

6. The injection molded article according to claim 1 or 2, wherein: It also includes a first detection electrode formed on the first surface, the first detection electrode is electrically connected to the first conductive layer, and detects a touch input position. The first conductive layer is a first wiring that transmits a signal detected by the first detection electrode. The second conductive layer is a second wiring that further transmits the signal transmitted from the first wiring through the conductive material.

7. A method for manufacturing an injection molded product, characterized in that: have: The step of placing a base sheet in a cavity of an injection molding mold with its second surface in contact with the cavity surface, wherein the base sheet has a first conductive layer formed on the first surface, a second conductive layer electrically connected to the first conductive layer via a conductive material completely filling a through-hole extending from the first surface to the second surface, and a sealing material formed on at least the first conductive layer to cover the through-hole; a step of injecting and filling the cavity with the molten resin while suppressing the molten resin from flowing through the conductive material with the sealing material; and The molten resin is cooled and solidified to form a molded resin body, and the base sheet is fixed to the surface of the molded resin body.

Images