JP5812207B2 - Flexible multilayer board - Google Patents

Description

  The present invention relates to a flexible multilayer substrate.

  An example of a flexible wiring board having a cut is described in JP 2011-124332 A (Patent Document 1). In this example, one of the portions adjacent to each other with the notch interposed therebetween is elastically deformed and bent, thereby increasing the degree of freedom of connection to other members.

  Japanese Patent Laying-Open No. 2004-259834 (Patent Document 2) describes an example of a flexible printed board having a cut. In this example, cutting is used to bend and connect a part of the flexible printed circuit board.

  FIG. 13 shows a first example of a flexible multilayer substrate having a cut. The flexible multilayer substrate 901 has a rectangular shape in plan view, and the electrodes 18 are arranged near both ends. In the flexible multilayer substrate 901, a cut 31 is formed from the short side when viewed in plan. The cut 31 is provided in a direction parallel to the long side. The individual parts divided by the cuts 31 are band-shaped and can be bent. FIG. 14 is a cross-sectional view taken along the line XIV-XIV in FIG.

  FIG. 15 shows a second example of the flexible multilayer substrate having a cut. The flexible multilayer substrate 902 is rectangular in plan view, and the electrodes 18 are arranged near the four corners. In the flexible multilayer substrate 902, cuts 31 are formed from both the long side and the short side when viewed in plan. The cut 31 is provided in a direction perpendicular to each side.

JP 2011-124332 A JP 2004-259834 A

  In order to connect to other members, when bending one of the adjacent parts with elastic deformation, the stress concentrates on the deepest part of the notch and breaks from this notch. There was a problem that it was easy to peel off.

  Then, an object of this invention is to provide the flexible multilayer substrate which is hard to be damaged or peeled off from the notch.

  In order to achieve the above object, a flexible multilayer substrate according to the present invention includes a laminate in which a plurality of resin layers are laminated and joined. The laminate has a notch penetrating in the thickness direction. As seen in a plan view, the cut extends from the outer periphery of the laminate to the cut end point inside the laminate, and a reinforcing structure is provided around the cut end point.

  According to the present invention, since the reinforcing structure is provided around the end point of the cut where stress tends to concentrate, it can be prevented from being damaged or peeled off starting from the cut.

It is a top view of the flexible multilayer substrate in Embodiment 1 based on this invention. It is arrow sectional drawing regarding the II-II line | wire in FIG. It is a top view of the 1st modification of the flexible multilayer substrate in Embodiment 1 based on this invention. It is arrow sectional drawing regarding the IV-IV line | wire in FIG. It is a top view of the 2nd modification of the flexible multilayer substrate in Embodiment 1 based on this invention. It is arrow sectional drawing regarding the VI-VI line in FIG. It is a top view of the flexible multilayer substrate in Embodiment 2 based on this invention. It is arrow sectional drawing regarding the VIII-VIII line in FIG. It is sectional drawing of the modification of the flexible multilayer substrate in Embodiment 2 based on this invention. It is a top view of the flexible multilayer substrate in Embodiment 3 based on this invention. It is arrow sectional drawing regarding the XI-XI line in FIG. It is sectional drawing of the modification of the flexible multilayer substrate in Embodiment 3 based on this invention. It is a top view of the 1st example of the flexible multilayer substrate based on a prior art. It is arrow sectional drawing regarding the XIV-XIV line | wire in FIG. It is a top view of the 2nd example of the flexible multilayer substrate based on a prior art.

(Embodiment 1)
With reference to FIG. 1 and FIG. 2, the flexible multilayer substrate in Embodiment 1 based on this invention is demonstrated. FIG. 1 is a plan view of a flexible multilayer substrate 101 in the present embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  The flexible multilayer substrate 101 in the present embodiment includes a laminate 3 in which a plurality of resin layers 2 are laminated and joined. A via conductor 16 and a conductor pattern 7 are disposed inside the multilayer body 3. The laminate 3 has a cut 31 that penetrates in the thickness direction. The cut 31 extends from the outer periphery of the multilayer body 3 to the cut end point 9 inside the multilayer body 3 in a plan view. A reinforcing structure is provided around the cut end point 9. Various structures can be considered as the reinforcing structure. FIG. 1 shows a preferred example of the reinforcing structure, which will be described next.

  In the flexible multilayer substrate in the present embodiment, the reinforcing structure includes a reinforcing layer 25 provided on the surface so as to be along the edge of at least one surface of the laminate 3 at least around the cut end point 9. Such a reinforcing layer 25 can be formed of resin. When such a reinforcing layer 25 is formed of resin, it can be formed by printing using a paste-like resin.

  In the present embodiment, since the reinforcing structure is provided around the cut end point 9 where stress is likely to concentrate at the deepest part of the cut, it can be prevented from being damaged or peeled off from the cut. . In particular, if the reinforcing structure is the reinforcing layer 25 provided on the surface so as to be along the edge of at least one surface of the laminate 3, it is preferable because the reinforcing layer can be reliably reinforced.

  The present invention may have a configuration in which a reinforcing structure is provided only around the cutting end point 9, but in FIG. 1, the reinforcing layer 25 as a reinforcing structure is provided not only around the cutting end point 9 but in a wider range. It has been. Such a configuration may be used.

  The position of the cut end point 9 may be arbitrarily set inside the stacked body 3 when viewed in plan. When joining the flexible multilayer substrate to other members, depending on the conditions such as how much to bend a part of the flexible multilayer substrate and how long to secure the length and width of the bent portion of the flexible multilayer substrate, The position of the cutting end point 9 is determined.

  In plan view, the reinforcing layer 25 is preferably provided over the entire circumference of the laminate 3. If the reinforcing layer 25 is provided in this way, the entire circumference can be reinforced, and the durability of the laminate is increased. If the reinforcing layer 25 is provided over the entire circumference in this way, the outer peripheral portion of the laminated body 3 is thickened by the amount of the reinforcing layer 25, so that the entire laminated body 3 is pressed for pressure bonding. The outer peripheral portion of the laminated body 3 is surely pressed. Therefore, it is possible to reliably perform crimping in the vicinity of the outer periphery, which is likely to be insufficient in general, which is preferable. Usually, crimping in the vicinity of the outer periphery tends to be insufficient because the thickness of the portion other than the vicinity of the outer periphery (hereinafter referred to as “inner portion”) when viewed from the top of the laminate 3 is increased by the conductor pattern 7 or the like. Because there is. Therefore, in the vicinity of the outer periphery where the thickness is smaller than that of the inner part, the pressure tends to be insufficient, and as a result, the pressure bonding tends to be insufficient.

  FIG. 3 is a plan view of the flexible multilayer substrate 102 of the first modification example of the present embodiment. As shown in FIG. 3, the reinforcing layer 25 is preferably disposed so as to extend to at least one side of the periphery around the cut end point 9. FIG. 4 shows a cross-sectional view taken along the line IV-IV in FIG. In the example shown in FIGS. 3 and 4, the reinforcing layer 25 extends in a substantially square shape around the cut end point 9. With such a configuration, the cut end point 9 can be reinforced more reliably.

  FIG. 5 is a plan view of the flexible multilayer substrate 103 of the second modification example of the present embodiment. The extending shape of the reinforcing layer 25 is not limited to the substantially square shape illustrated in FIGS. 3 and 4, and may be another shape. As long as it extends to at least one side of the periphery, the reinforcing layer 25 is arranged so as to extend in the extending direction of the cut 31 around the cut end point 9 as shown in FIG. Also good. The extension direction of the cut 31 is a direction from the start point of the cut 31 on the outer periphery of the laminated body 3 to the cut end point 9 inside the laminated body 3 in a plan view. In other words, this is the direction from the incision end point 9 toward the inside of the laminate 3 in plan view. FIG. 6 shows a cross-sectional view taken along the line VI-VI in FIG.

(Embodiment 2)
With reference to FIG. 7 and FIG. 8, the flexible multilayer substrate in Embodiment 2 based on this invention is demonstrated. FIG. 7 is a plan view of flexible multilayer substrate 104 in the present embodiment, and FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

  The basic configuration of the flexible multilayer substrate 104 in this embodiment is the same as that of the flexible multilayer substrate 103 described in Embodiment 1. The flexible multilayer substrate 104 in the present embodiment includes, as a reinforcing structure, a reinforcing layer 25 provided on the surface so as to follow the edge of at least one surface of the laminate 3 around the cut end point 9. The flexible multilayer substrate 104 is different from the flexible multilayer substrate 103 in the following points.

  In the flexible multilayer substrate 104, the reinforcing layer 25 includes a metal foil pattern 24 disposed so as to be in contact with the surface of the laminate 3. Therefore, the reinforcing layer 25 includes the resin portion and the metal foil pattern 24. As shown in FIGS. 7 and 8, the metal foil pattern 24 is arranged along the reinforcing layer 25 and is covered with a resin portion of the reinforcing layer 25.

  The resin layer 2 of the laminate 3 is generally obtained by patterning a metal foil of a resin sheet with a metal foil, but the metal foil pattern 24 shown in the present embodiment is the top layer and the top layer of the laminate. When the resin layer 2 forming the lower layer is processed, it can be obtained by leaving a part of the metal foil of the resin sheet with the metal foil as the metal foil pattern 24. The metal foil pattern 24 may be a copper foil pattern. Generally, since the laminated body 3 is created using the resin sheet with copper foil, it is easy to obtain the metal foil pattern 24 with copper foil.

  Also in this embodiment, the effects described in the first embodiment can be obtained. Further, in the present embodiment, the reinforcing layer 25 includes the metal foil pattern 24 disposed so as to be in contact with the surface of the laminated body 3, so that it is easy to apply pressure during pressure bonding. Further, since heat is transmitted through the metal foil pattern 24, the heat dissipation is improved by providing such a metal foil pattern 24.

  When viewed in a cross-sectional view, the structure shown in FIG. 9 instead of FIG. 8 may be used. That is, the metal foil pattern 24 included in the reinforcing layer 25 may be exposed from the side surface of the reinforcing layer 25. The metal foil pattern 24 included in the reinforcing layer 25 may extend over the entire width of the reinforcing layer 25. By adopting this configuration, heat dissipation can be further improved.

  In FIG. 8 and FIG. 9, the reinforcing layer 25 is disposed on both the upper and lower surfaces, and the metal foil pattern 24 is provided in the reinforcing layer 25 on both the upper and lower surfaces. Even when the reinforcing layer 25 is provided on only one of the upper and lower surfaces instead of the upper and lower surfaces, a certain effect can be obtained by arranging such a metal foil pattern 24 in the reinforcing layer 25. .

  In the first and second embodiments, the reinforcing layer 25 is shown as a structure protruding from the outermost resin layer 2 when viewed in a cross-sectional view, but this is merely an example, and is not limited to this structure. . The flexible multilayer substrate may have a structure in which the reinforcing layer 25 is embedded in the outermost resin layer 2 and is so-called smooth. That is, a structure in which the surface of the resin layer 2 and the surface of the reinforcing layer 25 are located on the same plane may be employed. Such a structure can be obtained, for example, by performing pressing for flattening again at a temperature higher than the softening temperature of the resin layer 2 and lower than the pressure bonding temperature using a flat metal mold.

(Embodiment 3)
With reference to FIG. 10, FIG. 11, the flexible multilayer substrate in Embodiment 3 based on this invention is demonstrated. FIG. 10 is a plan view of flexible multilayer substrate 201 in the present embodiment, and FIG. 11 is a cross-sectional view taken along line XI-XI in FIG.

  The flexible multilayer substrate 201 in the present embodiment includes a laminate 3 in which a plurality of resin layers 2 are laminated and joined. The laminate 3 has a cut 31 that penetrates in the thickness direction. The cut 31 extends from the outer periphery of the multilayer body 3 to the cut end point 9 inside the multilayer body 3 in a plan view. A reinforcing structure is provided around the cut end point 9. In this reinforcing structure, around the cutting end point 9, the remaining resin layer 2 including the resin layer on at least one surface of the laminate 3 is left and the other resin layers 2 are further retracted from the cutting end point 9. It is a structure.

  In the present embodiment, the reinforcing structure is realized by leaving the resin layer 2 on the surface. However, with such a structure, stress concentration at the incision end point 9 can be reduced, so that the incision starts. Can be prevented from being broken or peeled off.

  In FIG. 11, the resin layer 2 is projected and left only on the lower surface of the multilayer body 3, but as shown in FIG. 12, the resin layer 2 may be projected and left on both upper and lower surfaces of the multilayer body 3.

  The reinforcing structure in the present embodiment exhibits a reinforcing effect particularly on the side where the tensile stress acts when bent. In the structure shown in FIG. 11, a portion (not shown) existing in the left and right continuations of FIG. 11 in the laminated body is bent, so that the bending end point 9 is bent in a direction that forms a downward convex curve. Especially when it comes to durability.

  With the structure shown in FIG. 12, since the resin layer 2 protrudes on both the upper and lower surfaces, durability can be exhibited against bending in either direction.

  In FIG. 11 and FIG. 12, when realizing the reinforcing structure, only one resin layer 2 per surface is left to protrude on the surface of the laminate, but it is not limited to only one layer. It is good also as projecting leaving two or more resin layers 2 per one surface.

  In order to obtain the reinforcing structure described in the present embodiment, a cut may be made before lamination in each of the resin sheets to be the resin layer 2 constituting the laminate 3. The resin sheet corresponding to the resin layer 2 to be left protruding as a reinforcing structure is provided with a cut up to the cut end point 9, and the resin sheet corresponding to the other resin layer 2 is cut so as to enter a position deeper than the cut end point 9. It should be provided. If the laminated body 3 is obtained by laminating and crimping resin sheets each having a predetermined cut, a flexible multilayer substrate having the reinforcing structure described in the present embodiment can be obtained.

  Up to this point, the description has been made on the assumption that a part of the plurality of resin layers 2 constituting the laminate 3 is protruded. However, a layer other than the resin layer 2 may be disposed as the protruded layer. The protruding layer may be a layer made of a material different from that of the resin layer 2.

  In each of the above embodiments, it is not specified whether or not a component is built in the laminate, but the present invention is naturally applicable even to a flexible multilayer board having a built-in component. It is.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used for a flexible multilayer substrate.

  2 resin layers, 3 laminates, 7 conductor patterns, 9 cut end points, 16 via conductors, 18 electrodes, 24 metal foil patterns, 25 reinforcing layers, 31 cuts, 101, 102, 103, 104, 201 Flexible multilayer substrate.

Claims (6)

Provided with a laminate in which a plurality of resin layers are laminated and joined,
The laminate has an incision penetrating in the thickness direction, and when viewed in plan, the incision extends from an outer periphery of the laminate to an incision end point in the laminate, and a reinforcement is provided around the incision end point. Structure is provided,
The reinforcing structure includes a metal foil pattern having a predetermined width disposed so as to contact the surface of the laminate, and a resin portion disposed on the metal foil pattern and formed to be equal to or larger than the width of the metal foil pattern. Flexible multilayer board. Provided with a laminate in which a plurality of resin layers are laminated and joined,
The laminate has an incision penetrating in the thickness direction, and when viewed in plan, the incision extends from an outer periphery of the laminate to an incision end point in the laminate, and a reinforcement is provided around the incision end point. Structure is provided,
The reinforcing structure is a structure in which another resin layer further recedes from the cut end point, leaving a part of the resin layer including the resin layer on at least one surface of the laminate around the cut end point. Flexible multilayer board.   The flexible multilayer substrate according to claim 1, wherein the reinforcing structure includes a reinforcing layer provided on the surface so as to be along an edge of at least one surface of the laminated body at least around the cut end point.   The flexible multilayer substrate according to claim 3, wherein the reinforcing layer is disposed so as to spread on at least one side of the periphery around the cut end point.   5. The flexible multilayer substrate according to claim 3, wherein the reinforcing layer is provided over the entire circumference of the laminate as viewed in a plan view.   The reinforcing structure is a structure in which another resin layer further recedes from the cut end point, leaving a part of the resin layer including the resin layer on at least one surface of the laminate around the cut end point. The flexible multilayer substrate according to claim 1.

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