TW201208501A - Flexible printed wiring board - Google Patents

Abstract

Provided is a flexible printed wiring board which has light-emitting elements mounted thereon by means of solder, and which makes it possible to achieve high heat dissipation and good flexibility at the same time. A flexible printed wiring board (1) in which a conductive layer (12) provided with a circuit section (12a) is laminated on the upper surface side of a substrate layer (11) and also heat dissipation layers comprising a metallic material having high heat conductivity are laminated on the lower surface side of the substrate layer (11), wherein a light-emitting element section (40) is mounted in part of the circuit section (12a) by means of solder and also the plurality of heat dissipation layers (13, 23) are laminated with resin layers interposed.

Description

201208501 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a flexible printed wiring board. More specifically, the present invention relates to a flexible printed wiring board in which a flexible printed wiring board constituting a light-emitting element through a solder can simultaneously achieve high heat dissipation and good flexibility. [Prior Art] / In recent years, as a long-life light-emitting element that can be saved with the improvement of power-light conversion efficiency, light-emitting diode (Light Emiuing)

Dl〇de, hereinafter referred to as LED), is used to illuminate. However, even if lED improves efficiency, it is a fact that nearly half of the input power is consumed as heat. Since the LED is inefficient due to the heat of the LED, how to dissipate heat becomes a problem. The two LEDs are of a size of about 3 to 1 mm, and are mounted on a circuit board after being mounted on a circuit board or directly formed on a circuit board. Further, as the circuit board, a flexible wiring board is generally used. For example, the following Patent Document 1 discloses a flexible printed wiring board in which such an LED is mounted. [Patent Document] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. 2002-84209. SUMMARY OF THE INVENTION Patent Document 1 relates to an invention of an illumination device. Beans and lowers, that is, in the process, the three-dimensional arrangement operation of the light-emitting diodes is moved to increase the yield, or the light-emitting efficiency is lowered as the temperature of the light-emitting diodes is lowered, thereby obtaining more High light output. In the flexible printed wiring board in which such an LED is mounted, as shown in the above Patent Document 1, a plurality of LEDs are generally mounted. Therefore, it is an important subject to improve heat dissipation characteristics. Therefore, in the past, in order to improve heat dissipation characteristics, a heat dissipation layer made of a metal foil layer was provided on the flexible printed wiring board. However, in the case of a flexible printed wiring board having such a heat dissipation layer, the heat dissipation layer is thickened in order to improve the heat dissipation characteristics of the south, and there is a problem that the flexibility is lowered. Therefore, the present invention solves the above problems of the prior art. A problem is to provide a flexible printed wiring board in which a flexible printed wiring board having a light-emitting element is mounted through a solder, and which can simultaneously achieve high heat dissipation and good flexibility. In the flexible printed wiring board of the present invention, a conductive layer having a circuit portion is laminated on the upper surface side of the substrate layer, and a heat dissipation layer made of a metal material having a high thermal conductivity is laminated on the lower surface side of the substrate layer. In addition, the first feature is that a part of the circuit portion is filled with a piece of electro-optic light through a solder, and a plurality of layers of the heat-dissipating layer are laminated via a resin layer. The layer has the feature of the first aspect of the present invention, in which the conductive layer of the t-way portion is formed on the upper surface side of the substrate layer, and the lower surface of the substrate layer is laminated with: a flexible layer of a metal material having a high rate of flexibility. In the printed wiring, a light-emitting element is mounted through the solder in the portion of the winding portion, and a plurality of layers of the heat-dissipating layer are laminated. Therefore, the flexible printed wiring board constituting the light-emitting member can achieve high heat dissipation. Further, in the flexible printed wiring board of the present invention, in addition to the above-mentioned 201208501 201208501, the second feature of the present invention is characterized in that the flexible printed wiring board is provided with a pre-bending curved portion and a predetermined non-bending portion. Non-bending #. Further, only the J "f structure is provided with the light-emitting element' and the number of layers of the layer laminated on the bent portion is less than the number of layers of the heat-dissipating layer laminated on the non-bending portion. According to the second aspect of the present invention, in addition to the effect of the first temple of the present invention, the flexible printed wiring board is provided with a predetermined bending, and the portion and the predetermined portion are not curved, and the curved portion is ... Only in the non-f-curve structure, a light-emitting element is mounted, and a layer of a heat-dissipating layer laminated on the curved portion is laminated. The number of layers of the heat dissipation layer in the non-bend portion of the sea can simultaneously achieve south heat dissipation and good bendability. Further, in addition to the above-described features of the present invention, the flexible printed wiring board according to the present invention is characterized in that the flexible printed wiring board is provided with a bending portion which is preliminarily bent and a non-bending ridge which is not bent. Also, only at . The sinuous non-bending portion is provided with the illuminating element, and the resin layer between the adjacent loose track layers is separated into two layers at the f-curved portion. According to the third aspect of the present invention, in addition to the above-described effects of the first aspect of the present invention, the flexible printed wiring board is provided with a predetermined curved portion and a curved portion and a non-bending portion which is not bent. Further, the light-emitting element is mounted only in the non-bending structure, and the 9-layer layer of the adjacent heat-dissipating layer is separated into two layers in the curved portion, so that high heat dissipation and good bendability can be simultaneously achieved. According to the flexible printed wiring board of the present invention, the flexible printed wiring board having the light-emitting element through the solder structure can simultaneously achieve high heat dissipation and good bendability. [Embodiment]

S 201208501 The embodiment of the flexible printed wiring board of the present invention will be described with reference to the following drawings to understand the present invention. However, the following description of the present invention is not intended to limit the scope of the claims. First, a flexible printed wiring board according to an embodiment of the present invention will be described with reference to Figs. 1 and 2 . The flexible printed wiring board of the embodiment of the present invention is a flexible printed wiring board that is disposed inside an electronic device (not shown) in a state in which the light-emitting element portion 4 is mounted through the solder portion 30. As shown in Fig. 1A, the flexible printed wiring board is composed of two flexible printed wiring boards of a flexible printed wiring board 10 and a flexible printed wiring board 2. The flexible printed wiring board 10 is a so-called double-sided flexible printed wiring conductive layer 12, a heat dissipation layer 13, and a board. As shown in Fig. 1A, the flexible printed wiring board 10 is composed of a substrate layer J^ and a cover film layer 14. The substrate layer 11 is formed of an insulating resin film as a base of the flexible printed wiring board.

ester. In addition, as the heat-resistant resin, for example, a polyimide resin 201208501 oxy-resin or the like is generally used as a heat-resistant resin for forming a flexible printed wiring board. In addition, as the substrate layer, a so-called metal laminate having a conductive layer made of a conductive metal such as a resin may be laminated on the surface of the resin film. As shown in FIG. 1a, the conductive layer 12 is formed on the substrate layer i (the metal case layer of the upper side of the substrate layer 1 for forming the circuit portion 12a of the flexible printed wiring board 1). In the present embodiment, the conductive layer 12 is included. In the circuit portion 12a (not shown), the plurality of circuit portions 12a of 2a have one portion of the circuit portion 12a through the solder portion, and the light-emitting device portion 4?? having the light-emitting element 41 is more specifically shown in FIG. The upper surface of the portion of the circuit portion 12a is disposed so as not to be covered with the cover film layer, and the light-emitting element portion 40 is disposed on the upper surface through the solder portion 3 (the upper portion of the circuit portion 12a). In the present embodiment, the conductive layer 12 is formed of copper. Of course, it is not limited to copper, and is electrically conductive as a circuit for forming a flexible printed wiring board. The thickness of the conductive layer 12 is preferably 35 "m. The first heat dissipation layer. The heat dissipation layer 13, as shown in Fig. 1A, is on the lower side of the substrate layer u. The layered gold U layer is mainly used as the light-emitting element portion 4 In the case of the structure of the (S), or the light-emitting element 4R0N_0FF, etc., it is applied to the tanner part, such as the implementation of the 201200801. In addition, in the present embodiment, the divergence "', s 13 is formed of copper. Of course, it is not limited to steel. As long as it is a metal material of heat conductivity, it is possible to obtain a metal material such as Fenga. The above-mentioned cover film layer 1.4 can be connected to a resin layer of an insulating layer such as a dragon-shaped printed wiring board 10. The film layer 14 can be used for the use of the polyimide film, the photosensitive photoresist, the liquid photoresist, etc. with the carrier. Moreover, the thickness of the cover film layer 14 is better than that of the flat parent. Preferably, the flexible printed wiring board 2 is a flexible printed wiring board of the early morning surface, as shown in FIG. 1A, and is composed of a substrate sound 21: a 21 heat dissipation layer 23. The substrate layer 2 1 and the heat dissipation layer 23 are squid, and the substrate layer U and the heat dissipation layer 13 々曰丨j members of the above flexible printed wiring board 10 have the same functions. The flexible printing is performed by an adhesive such as a thermosetting adhesive (not shown) as shown in Fig. 1A. The heat dissipation layer 23 of the wiring board 20 is adhered to the cover layer 4 of the covered heat dissipation layer 13 of the flexible printed wiring board 10 to form the flexible printed wiring board 1. With the above configuration, the plurality of heat dissipation layers 23 can be formed. The flexible printed wiring board i of the heat dissipation layer, more specifically, the flexible printed wiring including the heat dissipation layer 13 as the ith heat dissipation layer and the heat dissipation layer 23 as the second heat dissipation layer Therefore, it is possible to form a flexible printed wiring board 1 which is capable of dissipating heat dissipation. Further, the thickness of the heat dissipation layer 13 of the first heat dissipation layer is preferably 35 centimeters, and the second heat dissipation layer The thickness of the heat dissipation layer 23 is preferably 35 to 15 centimeters. 9 201208501 That is, as shown in Fig. 1A, the M: f n 7 flexible printed wiring board 1 is placed on the casing 50 of the electronic device. Therefore, the heat transmitted from the solder portion 3 to the flexible printed wiring board i is finally obtained from the time when the Lugu-from the time of the assembly of the first portion 40 or the light-emitting element 4k〇N-〇FF. Although the casing 5G dissipates heat, the heat radiated from the solder portion 3G to the flexible printed wiring board 1 can be dissipated more quickly and efficiently by the configuration including the plurality of heat dissipation layers. More specifically, as shown by the dotted arrow and the broken line ellipse in FIG. 1A, the heat transmitted from the solder portion 30 to the flexible printed wiring board can be gradually diffused in the area facing the junction with the body 50. Heat transfer in the state. Therefore, the heat transmitted from the solder portion 30 to the flexible printed wiring board can be quickly and efficiently dissipated from the body 50. Therefore, the flexible printed wiring board 1 capable of achieving high heat dissipation can be constructed. On the other hand, as shown in FIG. 1B, the conventional flexible printed wiring board 60 which does not have a heat dissipation layer cannot be conducted from the solder portion 30 to the flexible printing as indicated by a broken line arrow and a broken line ellipse in FIG. 1B. The heat of the wiring board 6 传热 is transferred in a state of being gradually diffused toward the surface area of the junction with the body 50. Therefore, the heat transmitted from the solder portion 30 to the switchable printed wiring board 60 is only partially transmitted to the casing 50, and rapid and highly efficient heat dissipation cannot be performed. The heat from the solder portion 3.0 to the flexible printed wiring board 60 cannot be sufficiently dissipated. In the case where such heat dissipation is insufficient, cracks or the like may occur in the solder portion 3, resulting in a decrease in reliability of electrical and mechanical connection. Moreover, the life of the product of the light-emitting element 41 is shortened. Further, such heat dissipation is insufficient, and a flexible printed wiring board having only one heat dissipation layer is similarly likely to be generated. In the case of the conventional flexible printed wiring board, the same components as those of the flexible printed wiring board of the present embodiment are provided with the same functions, and the same reference numerals are given in FIG. 1B to omit the same. Detailed description. In the present embodiment, the flexible printed wiring board 1 capable of achieving high heat dissipation can be constructed by providing a plurality of heat dissipation layers. Therefore, it is possible to form a flexible printed wiring board that can prevent the occurrence of cracks in the solder portion 30 and realize electrical and mechanical connection reliability. Further, the flexible printed wiring board 1 capable of preventing the life of the product of the light-emitting element 41 from being shortened can be constructed. Further, as shown in FIG. 2, the flexible printed wiring board 1 is provided with a curved portion K which is predetermined to be bowed and a non-curved portion F which is not bent, and only the non-curved portion F is provided with the light-emitting element 41. The light emitting element portion 40. Further, the number of layers of the heat dissipation layer laminated on the curved portion K is smaller than the number of layers of the heat dissipation layer laminated on the non-curved portion F. More specifically, as shown in Fig. 2, only one heat dissipation layer 13 is laminated on the curved portion κ, and two heat dissipation layers 13, 23 are laminated on the non-curved portion F. According to the above configuration, the flexible printed wiring board 1 capable of achieving both high heat dissipation and good flexibility can be constructed. Further, in the present embodiment, in the flexible printed wiring board 2, the heat dissipation layer 23 corresponding to the portion corresponding to the bent portion κ is removed by etching, whereby the laminate can be bent. The number of layers of the heat dissipation layer of 卩K is less than the number of layers of the heat dissipation layer laminated to the non-bend portion F.曰 Of course, it is not limited to this formation method, and any formation method may be employed as long as the number of layers of the heat dissipation layer laminated on the 邛κ layer is less than the number of layers of the heat dissipation layer laminated on the non-bend portion F. In addition, in the present embodiment, by removing the heat dissipation layer 23 of the flexible printed wiring board 20 corresponding to the f-curved portion κ, the number of layers of the heat dissipation layer laminated on the curved portion κ can be made smaller than that of the non-bending layer. "The layer of the heat dissipation layer I. However, it is not limited to this configuration. By removing only the heat dissipation layer U of the flexible printed wiring board 对应 corresponding to the bent portion κ, the number of layers of the heat dissipation layer laminated on the curved portion κ is smaller than the number of layers of the heat dissipation layer laminated on the non-curved portion F. can. Further, the number of layers of the heat dissipation layer in which the f-curved portion and the non-f-curved portion F are laminated is not limited to the number of layers in the present embodiment. The number of layers of the heat dissipation layer laminated on the bent portion κ can be appropriately changed as long as the number of layers of the heat dissipation layer laminated on the non-curved portion F is smaller. Further, in the present embodiment, the light-emitting element 40' is disposed only in the circuit portion 12a where the non-bending portion F is formed, but the configuration is not limited thereto. The light-emitting element portion (10) may be formed in the circuit portion 12a formed across the non-bending portion F and the f-curved portion K. However, in this case, it is necessary to focus on the light-emitting element portion 40° only in the non-test section F. In addition, the range of the curved portion κ and the non-bending portion ρ is shown to cover the cover layer of the heat dissipation layer U. Below the layer 14 is a reference illustration. The solder portion 30 is used to connect the light-emitting element portion 4. It is fixed to the (4) printed wiring board and electrically connects the circuit portion 12a and the light-emitting element portion. In addition, the thickness of the solder forming the solder portion 30 is preferably from 1 300 to 300 μm. The light-emitting element portion 40 is a so-called light-emitting element unit that is mounted with a light-emitting element. The light-emitting element 41, the ceramic package 42, and the resin mold 43 constitutes.

S 12 201208501 The light-emitting element 41 1 is an integrated circuit including a light-emitting portion (not shown) that converts a digital signal from the circuit portion 12a of the flexible printed wiring board 成 into an optical signal to emit light. Further, in the present embodiment, as the light-emitting element 4, a light-emitting diode (LED) made of gallium nitride is used. § However, the material for forming the LED is not limited to gallium nitride, and may be appropriately changed depending on the color of the light. Further, although not shown, the light-emitting element 41 includes a metal lead that electrically connects the electrode and the electrode to the solder portion 30. The ceramic package 42 is a ceramic substrate on which a base of the light-emitting element 41 is mounted. Further, in the present embodiment, the ceramic package 42 is formed of aluminum nitride. Of course, it is not limited to aluminum nitride, and any user can be used as a material for forming a ceramic substrate on which a light-emitting element is mounted. The resin mold 43 is an insulating resin for preventing defects such as disconnection or corrosion of the metal lead which is not provided in the light-emitting element 41. As the insulating resin, any user who is a resin mold for forming a light-emitting element unit, such as an epoxy resin, may be used. Next, a method of forming the flexible printed wiring board 1 in which the light-emitting element compensating portion 4 is formed by the solder portion 30 will be described. Referring to Fig. 2A, first, a flexible printed wiring board 10 having a circuit portion covered with a cover film layer 14 other than a connection portion of the solder portion 3A is provided on the upper surface of the substrate layer 12a, and under the substrate layer 13 201208501, the heat dissipation layer 13 covered by the cover film layer 14 is provided. Next, the flexible printed wiring board 20 is provided, and the flexible printed wiring board 20 is provided with a heat dissipation layer 23 on the upper surface of the substrate layer 21, which is etched away from the portion corresponding to the curved portion K. Then, on the lower surface of the cover film layer 14 covering the heat dissipation layer 13, a heat-curable adhesive (not shown) is adhered to the heat dissipation layer 23 side of the flexible printed wiring board 20. The flexible printed wiring board i is formed in the above manner. Then, the light-emitting element portion 4 is configured to pass through the solder portion 30 on the surface of the circuit portion 12a which is not covered with the cover film layer 14. Through the above steps, the flexible printed wiring board i in which the light-emitting element portion 4A is formed by the solder portion 30 is formed. Of course, the method of forming the flexible printed wiring board 1 in which the light-emitting element portion 4 is configured by the solder portion 30 is not limited to this configuration, and can be appropriately changed. Further, in Fig. 2, the size of the solder portion 3 and the light-emitting element portion is conveniently shown to be smaller than the size of the flexible printed wiring board. As shown in FIG. 2B, the flexible printed wiring board 配置 is disposed in an electronic device (not shown) in a state in which only the bending of the wisdom is bent: K is bent, and the embodiment of the present invention can be described with reference to FIG. 3 . A variant of the sturdy print slab. The non-deformation is made. The other components are the same as the above-mentioned ones. Therefore, if the J component has the same function, it is called Ding Yu to ask for a symbol to omit its detailed description.

S 14 201208501 明. As shown in Fig. 3, in the present modification, the light-emitting element 40 is disposed only in the non-bending portion f, and the resin layer between the adjacent heat-dissipating layers is separated into two layers in the bent portion κ. More specifically, the cover film layer 24 is laminated only on the portion of the heat dissipation layer 23 of the flexible printed wiring board 2 and the portion made of the bend κ, except for the cover film layer 24. The flexible printed wiring board 1〇 and the flexible printed wiring board 2〇 are bonded to each other by an adhesive such as a thermosetting adhesive (not shown). According to the above configuration, as shown in FIG. 3, when the flexible printed wiring board i 4 is placed in a state where it is placed inside an electronic device (not shown), the adjacent heat dissipation layer can be formed in the curved portion κ. The resin layers of 13, 23 are separated into two layers through the gap portion s. Therefore, the flexible printed wiring board 1 which can achieve good flexibility even when the curved portion κ has a configuration of a plurality of heat dissipation layers can be formed. Therefore, the switchable printed wiring board 1 capable of achieving both high heat dissipation and good bendability can be constructed. Further, in Fig. 3, the range of the curved portion Κ and the non-bent portion F is shown as a reference on the lower surface of the cover film layer 14 covering the heat dissipation layer 13. Further, in the present embodiment and the modified example, the flexible printed wiring board 1 is formed of two flexible printed wiring boards of the so-called double-sided flexible printed wiring board 10 and the so-called single-sided flexible printed wiring board 20. However, the configuration is not limited thereto, and the number of the flexible printed wiring boards forming the flexible printed wiring board 1 and the configuration (so-called double-sided or single-sided flexible printed wiring board) can be appropriately changed. Further, the number of the circuit portion 12a and the light-emitting element portion 40, the arrangement position of the light-emitting element portion 15 201208501 40 in the non-curved portion ρ, the size of the non-curved portion f and the curved portion κ, and the like are not limited to the embodiment, and may be appropriately change. According to the present invention, since the flexible printed wiring board in which the light-emitting element is mounted through the solder can simultaneously achieve high heat dissipation and good bendability, the electronic device having the flexible printed wiring board in which the light-emitting element is mounted through the solder is provided. The industry in the field of machines is highly utilized. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a main portion of a flexible printed wiring board in which a light-emitting element is mounted through a solder. Fig. i is a view showing a flexible printed wiring board according to an embodiment of the present invention. Fig. 1B is a view showing a conventional flexible printed wiring board. Fig. 2 is a cross-sectional view showing a simplified display of a switchable printed wiring board according to an embodiment of the present invention. Fig. 2A shows the state before the flexible printed wiring board is matched. Fig. 3 is a simplified cross-sectional view showing a modification of the flexible form of the embodiment of the present invention. [Main component symbol description] 1 Flexible printed wiring board 10 Flexible printed wiring board 11 Substrate layer 12 Conductive layer 12a Circuit part 13 Heat dissipation layer

S 16 201208501

14 20 21 23 24 30 40 41 42 43 50 60 61 62 62a 64 FKS Cover film flexible printed wiring board substrate layer Heat dissipation layer Cover film solder part Light-emitting element part Light-emitting element Ceramic package Resin mold housing flexibility Printed wiring board substrate layer conductive layer circuit portion cover film layer non-bending portion curved portion void portion 17

Claims (1)

201208501 VII. Patent application scope: 1. A flexible printed wiring board in which a conductive layer having a circuit portion is laminated on an upper surface side of a substrate layer, and a metal material having a high thermal conductivity is laminated on a lower surface side of the substrate layer. The heat dissipation layer is characterized in that a light-emitting element is mounted through a portion of the circuit portion through a solder, and a plurality of layers of the heat dissipation layer are laminated via a resin layer. 2. The flexible printed wiring board according to claim 2, wherein the flexible printed wiring board is provided with a bent portion of a predetermined curvature, and the non-bending portion is not in the non-bending portion. The light-emitting element is mounted such that the number of layers of the heat dissipation layer laminated on the curved portion is less than the number of layers of the heat dissipation layer laminated on the non-bending portion. 3. In the first aspect of the patent application, the flexible printed wiring board is provided with 11 printed wiring boards, wherein the 'non-bending portion of the oil is only bent at the bent portion of the non-bending portion. The tree between the adjacent heat dissipation layers: the light-emitting element, and is separated into two layers. Eight, schema: (such as the next page)