Molded component and method for manufacturing molded component

Abstract

Provided are a molded component and a method for manufacturing the molded component, whereby a contact defect of an electronic component or the like mounted on a circuit board does not easily occur, even if a design surface has a curved surface shape.　A molded component 100 according to the present disclosure comprises: a base layer 10 made of a synthetic resin and having a plate-like shape; a first film layer 30 having a curved surface region C and provided on one surface of the base layer 10; and a second film layer 20 provided on the other surface of the base layer 10 and provided as a circuit board having a component mounting region E. The molded component 100 is characterized in that the component mounting region E of the second film layer 20 and opposing the curved surface region C has a plurality of planar regions 21.

Description

Molded parts and methods for manufacturing molded parts

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to molded components incorporating circuit boards and methods for manufacturing molded components.

[0002] Conventionally, development has been underway on conductive circuit integrated molded products in which a film material is placed on one side of a plate-shaped resin substrate as a design surface that creates an aesthetic impression, and a film-like conductive circuit is placed on the other side and integrated (for example, Patent Document 1, etc.).

[0003] Patent No. 5553696

[0004] However, in the above-mentioned conductive circuit integrated molded product, if the design surface has a curved shape, the conductive circuit is also arranged along the curved shape, so that the electronic components are mounted at an angle to the conductive circuit, which can cause poor contact and the like, and there is room for improvement in this regard.

[0005] The present disclosure has been made in consideration of these problems, and its purpose is to provide a molded part and a method for manufacturing a molded part that are less likely to cause contact defects in electronic components mounted on a circuit board, even when the design surface has a curved shape.

[0006] In order to solve the above-mentioned problems, the molded part of the present disclosure is a molded part comprising: [1] a base layer made of synthetic resin and having a plate-like shape; a first film layer having a curved area provided on one surface of the base layer; and a second film layer provided on the other surface of the base layer and configured as a circuit board having a component mounting area, wherein the component mounting area facing the curved area in the second film layer has a plurality of flat areas.

[0007] Furthermore, in the molded part of the present disclosure, [2] in the configuration described in [1] above, it is preferable that the thickness unevenness of the base layer overlapping each of the plurality of planar regions is set to a predetermined value or less.

[0008] Furthermore, the molded part of the present disclosure has the following configuration: [3] In the configuration described in [1] or [2] above, it is preferable that each component mounted on the second film layer is arranged so as to fit within one of the plurality of planar areas.

[0009] The present disclosure also provides a method for manufacturing a molded part: [4] A method for manufacturing a molded part according to any one of [1] to [3] above, characterized in that it includes: arranging the first film layer on a cavity surface of a first mold having the shape of the curved region; arranging the second film layer on a cavity surface of a second mold having the shapes of the plurality of flat regions; and closing the first mold and the second mold, and injecting molten resin into the cavity to form the molded part.

[0010] According to the present disclosure, it is possible to provide a molded part and a method for manufacturing a molded part that are less likely to cause contact defects in electronic components mounted on a circuit board, even when the design surface has a curved shape.

[0011] Fig. 2 is a perspective view of a molded part according to an embodiment of the present disclosure, as seen from the functional surface side. Fig. 3 is a cross-sectional view taken along the line A-A in Fig. 1. Fig. 4 is a conceptual diagram in which the cross section of a molded part according to an embodiment of the present disclosure is enlarged in the thickness direction to make the flat area easier to see. Fig. 5 is a flowchart showing a method for defining flat areas in a molded part according to an embodiment of the present disclosure. Fig. 6 is a flowchart showing the steps of a method for manufacturing a molded part according to an embodiment of the present disclosure.

[0012] The present disclosure will now be described in more detail with reference to the drawings.

[0013] 1 shows a molded part 100 according to an embodiment of the present disclosure, which has a plate-like shape with a generally egg-shaped outline. The top surface (the surface on the negative side of the Z axis) in FIGS. 1 and 2 constitutes a functional surface F that is recessed downward in the figure (toward the positive side of the Z axis). In this embodiment, an electronic component (not shown) is mounted on functional surface F. Furthermore, functional surface F also has a shape that is recessed downward in the figure (toward the positive side of the Z axis) along the longitudinal direction of molded part 100, which is perpendicular to the A-A cross section.

[0014] Figure 3 is a conceptual diagram in which the cross-sectional view along the A-A cross section shown in Figure 2 is enlarged in the thickness direction (Z-axis direction) of molded part 100 to make it easier to visualize the flat area described below. Unlike Figure 2, Figure 3 depicts design surface D, which will be the outer surface of the final product using molded part 100, facing upward. It is anticipated that molded part 100 according to this embodiment will be aesthetically pleasing when viewed from the design surface D side.

[0015] The molded part 100 according to this embodiment includes a synthetic resin base layer 10 having a plate-like shape, a first film layer 30 having a curved surface area C on one surface (the design surface D side) of the base layer 10 and constituting the design surface D, and a second film layer 20 provided as a circuit board having a component mounting area E on the other surface (the functional surface F side) of the base layer 10. The component mounting area E facing the curved surface area C in the second film layer 20 has a plurality of flat areas 21.

[0016] In this embodiment, the base layer 10 can be made of synthetic resin materials such as polycarbonate (PC), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), and polymethyl methacrylate (PMMA). However, this is not limited to this embodiment, and other synthetic resin materials may also be used for the base layer 10. In particular, when using synthetic resin materials with high shrinkage rates, such as PP and ABS, for the base layer 10, there is a high possibility of sink marks and warping due to thick portions, and therefore the structure of the present disclosure is considered to be advantageous. Furthermore, polyethylene terephthalate (PET) is used as the substrate material for the first film layer 30 and the second film layer 20. However, this is not limited to this embodiment, and other synthetic resin materials may also be used. The second film layer 20 includes a conductive layer in addition to the PET substrate. Furthermore, a connector or the like may be installed for signal input / output to the second film layer 20, which functions as a circuit board.

[0017] It is preferable to select the substrate material for the first film layer 30 and the second film layer 20 taking into consideration the hardness and brilliance required for the design surface D, and the heat resistance temperature required when mounting components for the functional surface F.

[0018] In this embodiment, the entire area of ​​the design surface D, which is the top surface in Fig. 3, is the curved surface area C. However, this is not limited to this, and only a part of the area of ​​the design surface D may be the curved surface area C, and the other areas of the design surface D may be flat.

[0019] In this embodiment, as shown in FIGS. 1 and 3 , the area of ​​the functional surface F excluding the outer edge portion 21r is defined as a plurality of flat areas 21. The plurality of flat areas 21 are configured with flat surfaces, including approximately rectangular flat areas 21a, 21b, 21c, 21d, 21e, 21a2, 21b2, 21c2, 21d2, and 21e2 arranged in a grid pattern as shown in FIG. 1 . In this embodiment, the plurality of flat areas 21 have a plurality of flat surfaces with different inclinations. Note that, in this embodiment, electronic components or the like are not mounted on the outer edge portion 21r of the functional surface F, and therefore, the outer edge portion 21r of the functional surface F is a curved surface having the same curvature as the opposing design surface D. However, this is not limited to this embodiment, and the outer edge portion 21r of the functional surface F may also be configured as part of the plurality of flat areas 21.

[0020] In this embodiment, as shown in Fig. 3 , a base layer with a virtual thickness t is assumed, which has the same curved surface shape on the design surface D side as on the functional surface F side (the lower surface of the base layer is shown by a dashed line in Fig. 3 ). The ends of each flat region in the X-axis direction are positioned on the lower surface of this virtual thickness t. With this configuration, for example, the actual thickness of the base layer 10 overlapping the flat region 21c located at the center in the X-axis direction in Fig. 3 (the distance from the lower surface of the first film layer 30 to the upper surface of the flat region 21c in Fig. 3 ) is t + Δt at the center of the flat region 21c in the X-axis direction, and is t at the end of the flat region 21c in the X-axis direction. That is, the thickness variation of the flat region 21c in the X-axis direction is Δt. The base layer 10 overlapping the flat region 21c also has a thickness variation in the Y-axis direction. The reference thickness t of the base layer 10 can be set to, for example, 2.5 mm, and the thickness variation Δt can be set to, for example, a predetermined value of +0.5 mm or less. Setting the thickness variation Δt to a predetermined value of +0.5 mm or less here means that the thickness may increase up to +0.5 mm relative to the reference thickness t, but the thickness should not decrease below the reference thickness t.

[0021] In this embodiment, the thickness variation Δt of the base layer 10 is set to be equal to or less than a predetermined value in both the X-axis direction and the Y-axis direction. More specifically, as will be described later, when the thickness variation Δt exceeds a predetermined value in either the X-axis direction or the Y-axis direction, the number of divisions into the multiple planar regions 21 in that direction is increased, and each planar region is defined so that the thickness variation Δt of the base layer 10 in that direction is equal to or less than the predetermined value.

[0022] As described above, in this embodiment, the thickness variation Δt of the base layer 10 overlapping each planar region is configured to be equal to or less than a predetermined value in both the X-axis and Y-axis directions. This configuration reduces shrinkage differences resulting from differences in the solidification (cooling) rate of the molten resin between the thick and thin regions during molding of the base layer 10, thereby preventing warpage of the molded part 100 due to shrinkage differences. This configuration also prevents welds from forming due to differences in the solidification (cooling) rate of the molten resin between the thick and thin regions, which can lead to poor appearance of the molded part 100. Furthermore, density variations between the thick and thin regions due to variations in the flow of the molten resin during filling into the mold are reduced, thereby preventing sink marks in the thick-walled portions.

[0023] Next, a procedure for dividing the functional surface F into a plurality of planar regions 21 so that the thickness variation Δt of the base layer 10 is equal to or less than a predetermined value will be described with reference to FIG. 4 and other figures.

[0024] First, the designer of the molded part 100 determines the shape of the design surface D, which includes the curved surface region C (step S101 in FIG. 4). Note that the design surface D typically defines the outer shape of the final product in which the molded part 100 is used. In this embodiment, the entire design surface D is described as being the curved surface region C, but only a portion of the design surface D may be the curved surface region C. A curved surface is a surface that is not a flat surface and has a non-zero curvature in at least one of the X-axis and Y-axis directions. The curved surface may be any curved surface, such as the surface of a sphere, or the side surface of a cylinder or cone, or a combination thereof.

[0025] Next, the designer of the molded part 100 places a component mounting area E on the functional surface F (step S102 in FIG. 4). The component mounting area E is an area where components such as electronic components are mounted, and is determined based on the circuit layout of the circuit board, etc. In this embodiment, the area excluding the outer edge 21r on the functional surface F is determined as the component mounting area E. In this embodiment, the component mounting area E is a continuous area excluding the outer edge 21r, but this is not limited to this. For example, multiple discontinuous areas on the functional surface F may be defined as the component mounting area E.

[0026] The components mounted in the component mounting area E of the functional surface F include, for example, active elements such as transistors, ICs, diodes, and operational amplifiers, as well as passive elements such as resistors, coils, and capacitors, and auxiliary components such as relays, switches, connectors, other circuit boards, and wiring.

[0027] Next, the designer of molded part 100 arranges multiple flat areas 21 in component mounting area E, which faces curved area C (i.e., overlaps with curved area C in the planar direction) (step S103 in FIG. 4 ). In this embodiment, the entire design surface D is curved area C, so the multiple flat areas 21 are arranged in the entire component mounting area E.

[0028] In this embodiment, the plurality of planar regions 21 are all regions inside the frame-shaped outer edge portion 21r, including the substantially rectangular planar regions 21a, 21b, 21c, 21d, 21e, 21a2, 21b2, 21c2, 21d2, and 21e2 indicated by the reference numerals in Fig. 1. The plurality of planar regions 21 may be substantially rectangular, triangular, or polygonal, or may include a planar region at least partially surrounded by a curve.

[0029] Each component mounted in the component mounting area E of the functional surface F is preferably arranged so as to fit within a single planar area. Here, "components fitted within a single planar area" means that the components do not protrude beyond the planar area when viewed from a direction perpendicular to the plane. This makes it less likely that poor contact will occur with electronic components mounted on the circuit board of the functional surface F. However, this is not limited to this configuration, and components may be arranged across two or more planar areas, taking into consideration the specifications of the components and / or the angle of inclination between adjacent planar areas.

[0030] Next, it is determined whether the thickness variation Δt of the base layer 10 overlapping each of the plurality of flat regions 21 is equal to or less than a predetermined amount (step S104 in FIG. 4 ). To determine the thickness variation Δt of the base layer 10, the thickness variation Δt of the base layer 10 overlapping each of the plurality of flat regions 21 inside the outer edge portion 21r is obtained from, for example, three-dimensional CAD data, and the flat regions whose thickness variation Δt exceeds the predetermined amount are listed. The thickness variation Δt is obtained in the X-axis direction and the Y-axis direction for each of the base layers 10 overlapping each flat region.

[0031] If the thickness variation Δt in the X-axis and Y-axis directions for all planar areas is less than a predetermined amount (Yes in step S104), the procedure for dividing the component mounting area E of the functional surface F opposite the curved area C into each of the multiple planar areas 21 is terminated.

[0032] On the other hand, if the thickness variation Δt of the base layer 10 overlapping any of the planar regions in at least one of the X-axis and Y-axis directions exceeds a predetermined amount (No in step S104), the number of divisions of the planar region in the direction in which the thickness variation Δt exceeds the predetermined amount is increased (step S105 in FIG. 4). For example, in FIG. 3, the left end in the X-axis direction has a larger curvature of the curved surface than the planar region 21c at the center in the X-axis direction, so it is divided into two planar regions 21a and 21b. In this way, by increasing the number of divisions of the planar region in the direction in which the thickness variation Δt exceeds the predetermined amount, the thickness variation Δt in that direction can be reduced compared to before the number of divisions was changed.

[0033] In step S105, the number of divisions of the planar area in the direction in which the thickness unevenness Δt exceeds the predetermined amount is increased, and then each component to be mounted in the component mounting area E is rearranged so that it fits within one planar area (step S106 in FIG. 4). Note that, as mentioned above, step S106 is not an essential procedure, but by rearranging each component so that it fits within one planar area, it is possible to make it less likely that poor contact will occur between electronic components and the like mounted on the circuit board on the functional surface F.

[0034] After executing step S106, the process returns to step S104 to determine whether the thickness variation Δt of the base layer 10 overlapping each of the planar regions 21 is equal to or less than a predetermined amount (step S104 in FIG. 4). Thereafter, steps S104 to S106 are repeated until the thickness variation Δt of the base layer 10 overlapping each of the planar regions 21 becomes equal to or less than the predetermined amount.

[0035] The molded part 100 is manufactured by insert molding, placing the first film layer 30 and the second film layer 20 in a cavity formed by a first mold and a second mold. To manufacture the molded part 100, the first film layer 30 is first placed on the cavity surface of the first mold, which has the shape of the curved surface region C (step S201 in FIG. 5 ). The second film layer 20, which serves as a circuit board, is then placed on the cavity surface of the second mold, which has the shape of the multiple flat surface regions 21 (step S202 in FIG. 5 ). At this time, the first film layer 30 and the second film layer 20 are suction-attached to the cavity surfaces of the first mold and the second mold, respectively, through suction holes provided in the first mold and the second mold. Note that steps S201 and S202 can be performed in any order, and step S202 may be performed first.

[0036] Next, the first and second molds are closed, and molten PC resin is injected into the cavity to perform insert molding (step S203 in FIG. 5 ). The injection pressure during this insert molding transfers the shape of the cavity surface of the first mold, which has the shape of the curved region C, to the first film layer 30, resulting in a molded part 100 in which the first film layer 30, which has the curved region C, serves as the design surface D. Similarly, the shape of the cavity surface of the second mold, which has the shapes of the multiple flat regions 21, is transferred to the second film layer 20, resulting in a molded part 100 in which the second film layer 20, which has the multiple flat regions 21, serves as the functional surface F.

[0037] Next, components that constitute the circuit are mounted on the component mounting area E on the functional surface F by means of soldering or the like (step S204 in FIG. 5).

[0038] As described above, this embodiment relates to a molded part 100 including a synthetic resin base layer 10 having a plate shape, a first film layer 30 having a curved surface region C provided on one surface of the base layer 10, and a second film layer 20 provided on the other surface of the base layer 10 as a circuit board having a component mounting region E. The component mounting region E facing the curved surface region C in the second film layer 20 is configured to have a plurality of flat surfaces 21. By adopting this configuration, even if the design surface D has a curved surface region C, the component mounting region E facing the curved surface region C has a plurality of flat surfaces 21. Therefore, electronic components mounted on the circuit board are positioned on each of the plurality of flat surfaces 21, preventing the electronic components from being tilted relative to the surface of the circuit board. This prevents problems such as poor contact.

[0039] In this embodiment, the thickness variation of the base layer 10 overlapping each of the planar regions 21 is set to a predetermined value or less. This configuration reduces shrinkage differences resulting from differences in the solidification (cooling) rate of the molten resin between the thick and thin regions during molding of the base layer 10, thereby preventing warpage of the molded part 100 due to shrinkage differences. This also prevents welds from forming due to differences in the solidification (cooling) rate of the molten resin between the thick and thin regions, which can lead to poor appearance of the molded part 100. Furthermore, density variations between the thick and thin regions resulting from variations in the flow of the molten resin during filling into the mold are reduced, preventing sink marks in the thick-walled portions.

[0040] In this embodiment, each component mounted on the second film layer 20 is configured to be positioned within one of the planar regions 21. By adopting such a configuration, it is possible to more reliably prevent electronic components and the like from being mounted on the circuit board in an inclined state.

[0041] This embodiment also provides a method for manufacturing a molded part 100, including the steps of: placing a first film layer 30 on a cavity surface of a first mold having the shape of a curved region C; placing a second film layer 20 on a cavity surface of a second mold having the shape of a plurality of flat regions 21; closing the first and second molds; and injecting molten resin into the cavity to form the molded part 100. By employing this configuration, even if the design surface D has a curved region C, the component mounting region E facing the curved region C has a plurality of flat regions 21. This ensures that electronic components mounted on the circuit board are positioned along each of the plurality of flat regions 21, preventing the electronic components from being tilted relative to the circuit board. This prevents problems such as poor contact.

[0042] Although the present disclosure has been described based on various drawings and examples, it should be noted that those skilled in the art can easily make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present invention. For example, the functions included in each component can be rearranged so as not to cause logical inconsistencies, and multiple components can be combined into one or divided. It should be understood that these modifications and alterations are also included in the scope of the present invention.

[0043] For example, in this embodiment, the area of ​​the functional surface F excluding the outer edge portion 21r is made into a plurality of planar areas 21, but this is not limited to this form, and all areas of the functional surface F including the outer edge portion 21r may be configured as planar areas.

[0044] Furthermore, in this embodiment, an example has been described in which the design surface D has a curved surface region C that is a convex surface, but this is not limited to this. The design surface D may also be configured to include a curved surface region C that is a concave surface. In this case, the base layer 10 overlapping each of the flat areas 21 facing the curved surface region C will be thicker at the end positions of each flat area than at the center position in the surface direction of each flat area by a thickness variation Δt, relative to the reference thickness t. In this case, too, the thickness variation Δt can be reduced by increasing the number of divisions of the flat area in the direction along the surface.

[0045] Furthermore, in the present embodiment, the reference thickness t of the base layer 10 is set to 2.5 mm, and the thickness variation Δt is set to a predetermined value of +0.5 mm or less. However, the present invention is not limited to this embodiment. The reference thickness t of the base layer 10 can be set to any value less than 2.5 mm or greater than 2.5 mm. The predetermined value for the allowable thickness variation Δt may be set to a value less than +0.5 mm to suppress the thickness variation Δt to a small value, or the predetermined value for the allowable thickness variation Δt may be set to a value greater than +0.5 mm to allow a large thickness variation Δt. Furthermore, the predetermined value for the allowable thickness variation Δt relative to the reference thickness t may be set to, for example, between −0.5 mm and +0.5 mm, and the thickness may be controlled to allow a thickness thinner than the reference thickness t.

[0046] Even if warping or the like occurs in molded part 100 due to environmental temperature, humidity, etc., and each of the planar regions 21 deviates slightly from a plane, they are still treated as planar regions.

[0047] REFERENCE SIGNS LIST 10 Base layer 20 Second film layer 21 Multiple flat areas 21a, 21b, 21c, 21d, 21e Flat areas 21a2, 21b2, 21c2, 21d2, 21e2 Flat area 21r Outer edge portion 30 First film layer 100 Molded part C Curved area D Design surface E Component mounting area F Functional surface

Claims

1. A molded part comprising: a synthetic resin base layer having a plate-like shape; a first film layer having a curved area provided on one surface of the base layer; and a second film layer provided on the other surface of the base layer as a circuit board having a component mounting area, wherein the component mounting area facing the curved area of ​​the second film layer has a plurality of flat areas.

2. The molded part according to claim 1, wherein the thickness unevenness of the base layer overlapping each of the plurality of flat areas is set to a predetermined value or less.

3. The molded part according to claim 1 or 2, wherein each component mounted on the second film layer is positioned so as to fit within one of the plurality of planar regions.

4. A method for manufacturing a molded part as described in claim 1 or 2, comprising: arranging the first film layer on a cavity surface of a first mold having the shape of the curved area; arranging the second film layer on a cavity surface of a second mold having the shape of the multiple flat areas; closing the first mold and the second mold, and injecting molten resin into the cavity to form the molded part.

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