JP4078723B2 - A flexible double-sided printed circuit board having a capacitor and a method for forming the capacitor. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionIsFlexible double-sided printed circuit board with capacitorsAnd formation method thereofIt is about.
[0002]
[Prior art]
  In the flexible double-sided printed circuit board, a circuit pattern including electrodes is formed on a conductive layer made of a conductive foil or the like formed on both sides of a flexible insulating base film. In addition, electronic components are mounted and soldered.
[0003]
  In recent years, as the demand for smaller and lighter electronic devices has increased, flexible double-sided printed circuit boards have also become thinner, the wiring gaps have been narrowed, the base film has been made thinner, and further, through-through has been accompanied by an increase in mounting density. The diameter of holes and the diameter of via holes in the case of a multi-layered structure of several layers are in progress.
[0004]
  The thin flexible double-sided printed circuit board as described above is used for applications that require lightness in addition to flexibility and bending durability. For example, a suspension part of a hard disk drive (HDD) or a liquid crystal panel circuit of a mobile phone It is particularly effectively used in a substrate, a CSP (Chip Scale Package) interposer, etc., which is required to be thin for IC card mounting.
[0005]
  As an example of such a flexible double-sided printed circuit board, when it consists of a copper foil and a polyimide layer formed as conductive layers on the first surface and the second surface, respectively, a polyimide liquid uncured material is used as the first copper foil. The polyimide layer is made into a flexible base film by applying to the surface and then covering with a second copper foil and curing at a curing temperature of about 300 degrees Celsius.
[0006]
[Problems to be solved by the invention]
  By the way, as shown in the cross-sectional view of FIG. 11, as a conventional method in the case of electrically connecting the circuit patterns formed respectively on the first and second conductive layers of the flexible double-sided printed circuit board, The through hole 101 was provided in the base film 100, and the electroless plating portion 102 was formed on the wall surface of the through hole 101, so that the circuit pattern 106 on the second surface was electrically connected to the circuit pattern 107 on the first surface. In this way, an electronic circuit is configured using the circuit patterns 105 and 107 respectively formed on the first surface of the flexible double-sided printed circuit board.
[0007]
  However, the connection by the through hole as described above has a drawback that a number of steps such as resist coating, drilling, plating, and resist removal related to through hole conduction processing are required, and the total man-hour is increased. It was.
[0008]
Furthermore, as the through-hole diameter becomes smaller and the through-hole depth becomes shallower, it becomes difficult to manage the roughness and shape of the through-hole wall surface, and the quality control of the formed plated layer and the plated layer on the through-hole wall surface As a result, there is a problem that the electrical and mechanical reliability of the connection portion is lowered.
[0009]
  In addition, when a capacitor is provided on a flexible double-sided printed circuit board, a capacitor configured as an independent single component is attached and connected between circuit patterns by soldering or the like, and thus a capacitor is required as a component. In addition, there is a drawback that an additional soldering process is required.
[0010]
  The present invention has been made to solve the above-described problems in the prior art, and can be easily connected in a small number of steps, and the reliability of the connecting portion is high.CoFlexible double-sided printed circuit board with capacitorsAnd method of forming capacitorThe purpose is to provide.
[0011]
[Means for Solving the Problems]
  To solve the problems of the prior artBookA flexible double-sided printed circuit board comprising a capacitor according to the invention has flexibility and has a predetermined dielectric constantε1A flexible double-sided printed circuit having a conductive layer formed on both sides of the first and second sides with an insulating film interposed therebetween, wherein the conductive layer and the non-conductive layer are formed on the first side of the flexible double-sided printed circuit board. An electrode plate is formed for connection, and the conductive layer on the first surface on the flexible double-sided printed circuit boardHas a predetermined dielectric constant ε2Covered with a dielectric film, the end of the flexible double-sided printed circuit board is wound together with the dielectric film with the first surface insideAndThe conductive layer on the second surface of the wound portion is electrically connected to the electrode plate formed on the first surface.A capacitor having a dielectric constant ε1 and a capacitor having ε2 are formed between the conductive layer on the first surface and the conductive layer on the second surface.It is characterized by that.
[0012]
  According to the above-described configuration, the insulating film is interposed between the conductive layers of the portion that is wound, and in addition, the dielectric that is wound between the two conductive layers that are adjacent to each other as a result of being wound. The film is interposed, and the capacitance of the formed capacitor increases due to the effect of the polarization of the dielectric film. In addition, the capacitor is formed on the flexible double-sided printed circuit board only by the configuration in which the end of the flexible double-sided printed circuit board is wound.
[0013]
  Furthermore, since the conductive layer on the second surface constituting one electrode of the capacitor is electrically connected to the electrode plate formed on the first surface, the connection terminals of both electrodes of the formed capacitor are both Formed on the first surface, the circuit pattern configuration is simplified. In addition, since the conductive layer on the second surface is bonded to the electrode plate on the first surface, a wide bonding surface can be secured, and flattening of the bonding surface can be facilitated, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved.
[0014]
  The method for forming a capacitor on a flexible double-sided printed circuit board according to the present invention is flexible and has a predetermined dielectric constant.ε1A capacitor is formed on a flexible double-sided printed circuit board having conductive layers formed on both sides of the first surface and the second surface with an insulating film provided therebetween, wherein the first on the flexible double-sided printed circuit board On the surface, an electrode plate is formed unconnected with the conductive layer on the first surface, and the conductive layer on the first surface on the flexible double-sided printed circuit board is formedAnd having a predetermined dielectric constant ε2Cover with a dielectric film, wrap the end of the flexible double-sided printed circuit board together with the dielectric film, with the first surface inside,In order to form a capacitor with a dielectric constant ε1 and a capacitor with a dielectric constant ε2,The conductive layer on the second surface of the wound portion is electrically connected to the electrode plate formed on the first surface.
[0015]
  According to the above-described method, the capacity of the formed capacitor is increased by interposing the insulating film and the dielectric film between the conductive layers of the part that is caught. Moreover, a capacitor is formed on the flexible double-sided printed circuit board simply by winding the end of the flexible double-sided printed circuit board.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is a part of a preferred example for showing the essential configuration and operation of the present invention. Therefore, there are cases where various limitations preferable in terms of the technical configuration may be attached. The scope of the invention is not limited to these forms unless otherwise specified in the following description.
[0017]
  FIG. 1 illustrates the present invention.Reference exampleIt is a schematic cross section of the flexible double-sided printed circuit board concerning. FIG. 2 is a schematic cross-sectional view showing the steps of the method for connecting the flexible double-sided printed circuit board shown in FIG. Further, FIG. 3 is a schematic cross-sectional view showing a step following FIG.
[0018]
  Reference exampleThe flexible double-sided printed circuit board 1 is a flexible double-sided printed circuit board incorporated in a smart file electronic device incorporating a semiconductor integrated circuit chip (IC), a capacitor, and an antenna. As shown in FIG. Is composed of an insulating and flexible base film 2 made of a polyimide resin film or the like. A wiring conductor made of copper foil or the like is provided on both surfaces of the base film 2 to form a conductive layer, and this conductive layer is etched to form a circuit pattern and an antenna.
[0019]
  Both surfaces are a first surface (front surface) and a second surface (back surface), respectively, and the first pattern electrode 6 and the second pattern electrode 7 formed by copper foil etching are formed on the conductive layer of the first surface. Are arranged independently. On the other hand, a circuit pattern 3 formed by a copper foil etching process is provided on the conductive layer on the second surface.
[0020]
  The end portion of the flexible double-sided printed circuit board 1 is folded at least twice so that the first surface is folded inward, so that a first folding portion R1 and a second folding portion R2 are sequentially formed. With this folding structure, the circuit pattern 3 on the second surface at the tip of the first folding portion R1 faces the first surface.
[0021]
  Here, the formation position of the second folding part R2 is adjusted, and the connection part 3a, which is a part of the circuit pattern 3 on the second surface at the tip of the first folding part R1, becomes the second on the first surface. The connection portion 3a and the second pattern electrode 7 are joined to each other by using a conductive material 8 made of metal solder, other hot melt material, conductive resin, or the like.
[0022]
  As beforeReference exampleAccording to the present invention, the conductive layer on the second surface of the folded portion is directly connected to the conductive layer on the first surface, so that the electric power of both conductive layers can be obtained without providing connection portions such as through holes and jumper wires according to the prior art. Therefore, it can be manufactured with a simple configuration and low cost.
[0023]
  AlsoReference example aboveAs with the conventional through-hole method, cross wiring is possible, so that a flexible double-sided printed circuit board with high mounting density and low cost can be realized.
[0024]
  In addition, by directly joining the circuit pattern on the second surface to the electrode on the first surface, a wide joint surface can be secured, and the flatness of the joint surface is easy, so that the electrical characteristics of the joint portion can be obtained. In addition, the mechanical strength can be improved.
[0025]
  Reference example aboveThe method for connecting a flexible double-sided printed circuit board according to the present invention provides a through-hole process between a first surface and a second surface of a base film as a substrate when an electronic circuit is formed using the flexible double-sided printed circuit board. In this method, the electrode or circuit pattern on one surface is directly joined to the electrode or circuit pattern on the other surface without using a jumper wire. Hereinafter, this connection method will be described in the order of steps with reference to the drawings.
[0026]
  As a first step, as shown in FIG. 2, a flexible double-sided printed circuit board WB in which conductive layers are formed on both the first surface Sf1 and the second surface Sf2 with a flexible insulating film 2 interposed therebetween. The first surface electrode Sf1 and the second surface electrode Sf2 are etched to form the first pattern electrode 6 and the second pattern electrode 7 on the first surface Sf1, and the circuit is formed on the second surface Sf2. Pattern 3 is formed.
[0027]
  Next, as shown in FIG. 3, one end Ej of the flexible double-sided printed circuit board WB is folded in the direction U1 in the drawing so that the first surface Sf1 is folded inward to form a first folding portion R1. Thereby, the upper and lower sides are reversed in the first folding part R1.
[0028]
  Next, as shown in FIG. 1, the flexible double-sided printed circuit board WB is folded once more in the direction U2 in the drawing so that the first surface Sf1 is folded inward. At this time, in consideration of the length necessary for connection, the first folding portion R1 is bent at a corresponding position so as to be at the position of the second pattern electrode 7. As a result, the second fold portion R2 is formed, and the top and bottom of the first fold portion R1 is further inverted so that the circuit pattern 3 disposed on the second surface Sf2 side is on the first surface Sf1 side. It is possible to contact the second pattern electrode 7 disposed on the opposite side.
[0029]
  Next, a portion where the circuit pattern 3 disposed on the second surface Sf2 side of the front end portion of the first folding portion R1 faces the second pattern electrode 7 disposed on the first surface Sf1 side is joined. 3a, the joint 3a and the second pattern electrode 7 are joined by the conductive material 8. As the conductive material 8, metal solder, other hot melt materials, conductive resins, and the like are suitable. Through the above operation, both sides of the circuit board can be made conductive.
[0030]
  By this method, the circuit pattern 3 formed on the conductive layer of the second surface Sf2 and the first surface Sf1 are formed without providing through holes, jumper wires or the like for conducting both surfaces of the conventional flexible double-sided printed circuit board. The second pattern electrode 7 formed on the conductive layer can be connected by a simplified process. Therefore, the number of processes can be reduced and the cost can be reduced as compared with the through hole plating process according to the conventional technique. Furthermore, since this method allows cross-wiring like the through-hole method, a high mounting density can be obtained.
[0031]
  In addition, compared with the conventional connection using the through hole, it is possible to secure a wide bonding surface between the bonding portion 3a of the second surface Sf2 and the second pattern electrode 7 of the first surface Sf1, and to flatten the bonding surface. By being easy, not only can the electrical characteristics of the joint portion be improved, but also the mechanical strength can be improved.
[0032]
  As described above, the flexible double-sided printed circuit board according to the reference example is the flexible double-sided printed circuit board in which the conductive layers are formed on both the first surface and the second surface with the insulating film having flexibility interposed therebetween. An electrode pattern is formed on one conductive layer, an end of the flexible double-sided printed circuit board is folded at least twice so as to fold the first surface inward, and the second surface of the folded portion The conductive layer is configured to be electrically connected to the electrode pattern on the first surface.
[0033]
According to the above configuration, the conductive layer on the second surface of the folded portion is connected to the conductive layer on the first surface, so that both conductive layers are electrically connected without applying connection means such as a through hole. Is done.
[0034]
  Moreover, if the conductive layer on the second surface is bonded to the conductive layer on the first surface, a wide bonding surface is ensured, and flattening of the bonding surface is easy, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface are connected with high reliability.
[0035]
  According to the flexible double-sided printed circuit board according to the reference example, the end portion is folded at least twice so that the first surface is folded inward, and the conductive layer of the second surface of the folded portion is formed on the first surface. Since it is configured to be electrically connected to the pattern, the electrical connection between the conductive layer on the second surface of the folded portion and the conductive layer on the first surface can be easily performed without using a through hole or a jumper wire. In addition, a flexible double-sided printed circuit board that can be realized at low cost can be provided. Moreover, the bonding surface between the conductive layer on the second surface and the conductive layer on the first surface is widened, and further flattening of the bonding surface facilitates not only the electrical characteristics of the bonded portion but also the mechanical strength. A flexible double-sided printed circuit board can be realized.
[0036]
  As a result, it is possible to provide a flexible double-sided printed circuit board in which a circuit pattern formed on the conductive layer on the second surface and a circuit pattern formed on the conductive layer on the first surface are connected easily and at low cost. .
[0037]
  The flexible double-sided printed circuit board connection method according to the reference example is the above-described flexible double-sided printed circuit board in which conductive layers are formed on both the first surface and the second surface across a flexible insulating film. A method of electrically connecting a conductive layer on one surface and a conductive layer on the second surface, The end of the flexible double-sided printed circuit board is folded at least twice so that the first surface is folded inward, and the conductive layer on the second surface of the folded portion is electrically connected to the conductive layer on the first surface. It is made to connect to.
[0038]
  According to the above method, since the conductive layer on the second surface of the folded portion is connected to the conductive layer on the first surface, electrical connection between the two conductive layers can be achieved without applying connection means such as a through hole. Made.
[0039]
  Moreover, if the conductive layer on the second surface is bonded to the conductive layer on the first surface, a wide bonding surface is ensured, and flattening of the bonding surface is easy, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface are connected with high reliability.
[0040]
  According to the flexible double-sided printed circuit board connection method according to the reference example, the end of the flexible double-sided printed circuit board is folded at least twice so that the first surface is folded inward, and the conductive layer on the second surface of the folded portion is formed. Since it is electrically connected to the conductive layer on the first surface, this method can be connected in a simplified process without providing a through hole or a jumper wire that conducts both surfaces of the flexible double-sided printed circuit board. The man-hours can be reduced and the cost is reduced.
[0041]
  In addition, the bonding surface between the conductive layer on the second surface and the conductive layer on the first surface can be widened, and the bonding surface can be easily flattened, so that not only the electrical characteristics of the bonding portion but also the mechanical strength can be improved. become. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface can be connected easily and at low cost.
[0042]
  FIG. 4 shows the first aspect of the present invention.1It is a schematic cross section of a flexible double-sided printed circuit board provided with a capacitor according to an embodiment. FIG. 5 is an explanatory diagram of capacitance formation of a flexible double-sided printed circuit board provided with the capacitor shown in FIG.
[0043]
  As shown in the figure, the flexible double-sided printed circuit board 11 provided with a capacitor is flexible and has a conductive layer 14 on the first surface across a base film 12 having a predetermined dielectric constant ε1. The conductive layer 13 is formed on the second surface with a large area, and the conductive layer 14 is provided with connection lands or connection terminals 16.
[0044]
  Furthermore, an electrode plate 17 is formed on the first surface so as not to be connected to the conductive layer 14. The electrode plate 17 is connected to a connection land or a connection terminal (not shown). Alternatively, the electrode plate 17 is also used as a connection land or a connection terminal.
[0045]
  Further, the conductive layer 14 on the first surface is covered with an insulating dielectric film 20 having a dielectric constant ε2, and the end of the flexible double-sided printed circuit board 11 is folded four times together with the dielectric film 20 with the first surface facing inward. In this way, a capacitor is formed. Reference numerals R11 to R14 denote folding parts.
[0046]
  Further, a portion of the conductive layer 13 on the second surface of the wound portion that faces the electrode plate 17 formed on the first surface is defined as a bonding portion 13 ′, and the bonding portion 13 ′ and the electrode plate 17 are Are electrically connected by a conductive material 18. For the conductive material 18, metal solder, other hot melt material, conductive resin, or the like is applied.
[0047]
  The capacitor formed as described above can be connected to a circuit pattern or other components by the connection terminal 16 and the connection land or connection terminal (not shown) connected to the electrode plate 17 or the electrode plate 17. ing.
[0048]
  Thus, according to the configuration of the present embodiment, both the connection terminals, that is, the electrode plate 17 or the connection land or connection terminal (not shown) connected to the electrode plate 17 and the connection terminal 16 are both flexible double-sided printed circuits. It is formed on the first surface of the plate 11.
[0049]
  According to the configuration of the present embodiment, the base film 12 having a dielectric constant ε1 is interposed between both the conductive layers 13 and 14, and in addition to this, both the conductive layers 13 that are in an adjacent state by being caught. 14 and 14 is interposed a dielectric film 20 having a dielectric constant ε2. As a result, the capacitance of the formed capacitor can be increased by the effect of polarization of the dielectric film 20.
[0050]
  FIG. 5 illustrates the above principle, and shows a part of the entrainment part equivalently. The conductive layer 14 on the first surface is opposed to the conductive layer 13 on the second surface through a base film having a dielectric constant ε1 and a thickness d1, and a capacitor C1 is formed by this portion. Here, C1 = A1 · ε1 / d1 (A1 is the area of the opposing conductive layer). The capacitance C1 is the same as the capacitance formed in a planar shape on which the flexible double-sided printed circuit board 11 is not wound.
[0051]
  In addition to the above, the conductive layer 14 on the first surface is further opposed to the conductive layer 13 on the second surface, which is in an adjacent state by being caught, via the sandwiched dielectric film 20, and this portion causes a capacitance. C2 is formed. Here, when the dielectric constant of the dielectric film 20 is ε2 and the thickness is d2, C2 = A2 · ε2 / d2 (A2 is the area of the adjacent conductive layer). The capacitor C2 is newly formed by winding the flexible double-sided printed circuit board 11 with the dielectric film 20 interposed therebetween.
[0052]
  As described above, according to this embodiment, it is possible to form a capacitor having an increased capacity such that C = A1 · ε1 / d1 + A2 · ε2 / d2, where C is the total capacitance.
[0053]
  As described above, in this embodiment, not only the base film 12 but also the dielectric film 20 sandwiched during winding is used as a dielectric, and the opposing and adjacent conductive layers 13 and 14 are used as electrodes, and the base film and the dielectric film. A capacitor is formed by the polarization characteristics.
[0054]
  Therefore, it is possible to provide a flexible double-sided printed circuit board in which a capacitor having a large capacity is formed on the board only by winding the end of the flexible double-sided printed circuit board with a dielectric film interposed therebetween.
[0055]
  Furthermore, since the conductive layer on the second surface constituting one electrode of the capacitor is electrically connected to the electrode plate formed on the first surface, the connection terminals of both electrodes of the formed capacitor can be Can also be formed on the first surface, thereby simplifying the circuit pattern configuration. In addition, since the conductive layer on the second surface is bonded to the electrode plate on the first surface, a wide bonding surface can be secured, and flattening of the bonding surface can be facilitated, so that only the electrical characteristics of the bonded portion can be improved. Therefore, it is possible to provide a flexible double-sided printed circuit board with a capacitor having improved mechanical strength.
[0056]
  Further, since the thickness of the folded and rolled-up portion can be reduced, a flexible double-sided printed circuit board having a small thickness can be obtained.
[0057]
  Unlike the configuration of the present embodiment, when the dielectric film 20 is wound without being sandwiched, the conductive layer 14 on the first surface and the conductive layer 13 on the second surface are in direct contact with each other due to the winding. The conductive layer 13 becomes conductive and is short-circuited, so that no capacitor is formed.
[0058]
  Also, the method for forming a capacitor on a flexible double-sided printed circuit board according to the present invention is flexible, and conductive layers are provided on both the first and second surfaces with an insulating film having a predetermined dielectric constant interposed therebetween. A capacitor is formed on the formed flexible double-sided printed circuit board.
[0059]
  As is apparent from the above, the steps include forming the electrode plate on the first surface of the flexible double-sided printed circuit board so as not to be connected to the conductive layer of the first surface; A step of covering one surface of the conductive layer with a dielectric film, a step of winding the end of the flexible double-sided printed circuit board together with the dielectric film, with the first surface facing inward, and the conductive layer of the second surface of the wound portion And a step of connecting the electrode plate formed on the first surface.
[0060]
  FIG. 6 illustrates the present invention.Other reference examplesIt is a top view which shows the process of the connection method of the flexible double-sided printed circuit board concerning this. FIG. 7 is a side view of FIG. Further, FIG. 8 is a plan view showing a process following FIG. 6, and FIG. 9 is a side view of FIG. FIG. 10 is a plan view showing a step following FIG.
[0061]
  As shown in FIGS. 6 and 7, the flexible double-sided printed circuit board 30 to which the present connection method is applied has electrodes 37 formed on the first surface with a flexible insulating film 32 interposed therebetween, and the second A conductive layer 33 is formed on the surface, and the end portion of the flexible double-sided printed circuit board 30 is elongated to form an elongated portion 30A.
[0062]
  As shown in FIG. 8 and FIG. 9, the end of the extending portion 30A is twisted 180 degrees in the direction of the arrow Tw to form the twisted portion 35, thereby reversing the first surface and the second surface. On the end side from the twisted portion 35, the conductive layer 33 on the second surface is on the upper side.
[0063]
  Next, as shown in FIG. 10, when the end portion of the extending portion 30A is bent in the direction of the arrow U with the second surface inside, the conductive layer 33 on the second surface on the end portion side becomes the lower side. By adjusting the folding position, the joining portion 33a which is a part of the conductive layer 33 is brought into contact with the electrode 37 on the first surface.
[0064]
  Next, the contact portion 33 a and the electrode 37 that are in contact with each other are bonded using the conductive material 38. As described above, the present invention provides the flexible double-sided printed circuit board 30 with the extending portion 30A, twists the extending portion 30A into a Mobius ring, and further folds the folded portion 30A so as to be folded up and down, so that the joint portion is a part of the conductive layer 33. 33a is joined to the electrode 37 on the first surface.
[0065]
  By this method, the conductive layer 33 on the second surface, the electrode 37 formed on the first surface, and the like, without providing a through hole or a jumper wire that conducts both surfaces of the conventional flexible double-sided printed circuit board, Can be connected in a simplified process. Therefore, the number of processes can be reduced and the cost can be reduced as compared with the through hole plating process according to the conventional technique. Furthermore, since this method allows cross-wiring like the through-hole method, a high mounting density can be obtained.
[0066]
  In addition, compared with the conventional connection using a through hole, it is possible to secure a wide bonding surface between the bonding portion 3a of the conductive layer 33 on the second surface and the electrode 37 on the first surface, and to flatten the bonding surface. By being easy, it is possible not only to improve the electrical characteristics of the joint portion but also to improve the mechanical strength.
[0067]
  In this way, the conductive layer on the second surface constituting one electrode of the capacitor is electrically connected to the electrode plate formed on the first surface, so that the connection terminals of both electrodes of the capacitor to be formed Both are formed on the first surface, and the circuit pattern configuration is simplified. In addition, since the conductive layer on the second surface is bonded to the electrode plate on the first surface, a wide bonding surface can be secured, and flattening of the bonding surface can be facilitated, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved.
[0068]
  Or the flexible double-sided printed circuit board which concerns on another reference example is said 1st of the flexible double-sided printed circuit boards by which the conductive layer was formed in both surfaces of the 1st surface and the 2nd surface on both sides of the insulating film which has flexibility. An electrode pattern is formed on the conductive layer of the surface, the end of the flexible double-sided printed circuit board is elongated, the end is twisted to invert the first surface and the second surface, and the end is Folded with the second surface inward, and the bent end The conductive layer on the second surface may be electrically connected to the electrode pattern on the first surface.
[0069]
  According to the above configuration, the connecting means such as a through hole is applied by connecting the conductive layer on the second surface of the portion that is twisted and inverted and further bent to the conductive layer on the first surface. Instead, both conductive layers are electrically connected.
[0070]
  Moreover, if the conductive layer on the second surface is bonded to the conductive layer on the first surface, a wide bonding surface is ensured, and flattening of the bonding surface is easy, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface are electrically connected with high reliability.
[0071]
  As described above, according to the flexible double-sided printed circuit board according to the other reference example, the elongated end portion is twisted so that the first surface and the second surface are reversed, and further, this end portion forms the second surface. Since the conductive layer on the second surface of the bent end is electrically connected to the electrode pattern formed on the conductive layer on the first surface, it is bent. It is possible to provide a flexible double-sided printed circuit board that realizes the electrical connection between the conductive layer on the second surface of the part and the conductive layer on the first surface easily and at low cost without using a through hole or a jumper wire. Moreover, the bonding surface between the conductive layer on the second surface and the conductive layer on the first surface is widened, and further flattening of the bonding surface facilitates not only the electrical characteristics of the bonded portion but also the mechanical strength. A flexible double-sided printed circuit board can be realized.
[0072]
  As a result, it is possible to provide a flexible double-sided printed circuit board in which a circuit pattern formed on the conductive layer on the second surface and a circuit pattern formed on the conductive layer on the first surface are connected easily and at low cost. .
[0073]
  Or the connection method of the flexible double-sided printed circuit board which concerns on another reference example is the flexible double-sided printed circuit board by which the conductive layer was formed in both surfaces of the 1st surface and the 2nd surface on both sides of the insulating film which has flexibility. A method of electrically connecting the conductive layer on the first surface and the conductive layer on the second surface, wherein the elongated double-sided end of the flexible double-sided printed circuit board is twisted and the first surface and the The second surface may be inverted, the end portion may be bent with the second surface inside, and the conductive layer on the second surface may be electrically connected to the conductive layer on the first surface.
[0074]
  According to the above method, the conductive layer on the second surface of the bent portion is twisted to be reversed and connected to the conductive layer on the first surface, so that connection means such as a through hole is not applied. Both conductive layers are electrically connected.
[0075]
  Moreover, if the conductive layer on the second surface is bonded to the conductive layer on the first surface, a wide bonding surface is ensured, and flattening of the bonding surface is easy, so that only the electrical characteristics of the bonded portion can be improved. First, mechanical strength is improved. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface are electrically connected with high reliability.
[0076]
  As described above, according to the connection method of the flexible double-sided printed circuit board according to the other reference example, the first and second surfaces are reversed by twisting the elongated end portion, and this end portion is further connected to the second portion. Folding with the side facing inward, and electrically connecting the conductive layer on the second side of the bent end to the electrode pattern formed on the conductive layer on the first side, this method allows flexible double-sided printing. Connections can be made in a simplified process without providing through holes, jumper wires, or the like for conducting both surfaces of the circuit board, and the number of steps can be reduced and the cost can be reduced.
[0077]
  In addition, the bonding surface between the conductive layer on the second surface and the conductive layer on the first surface can be widened, and the bonding surface can be easily flattened. By being able to be supported, it is possible to improve not only the electrical characteristics of the joint portion but also the mechanical strength. Thereby, the circuit pattern formed in the conductive layer on the second surface and the circuit pattern formed on the conductive layer on the first surface can be connected easily and at low cost.
[0078]
【The invention's effect】
  As detailed above, the present inventionSubcontractClaim1A flexible double-sided printed circuit board including the capacitor according to the first aspect has a conductive layer formed on both sides of the first side and the second side across a flexible insulating film having a predetermined dielectric constant, and is covered with a dielectric film. A capacitor that is wound from the end with the conductive layer on one surface inside is formed, and a conductive layer on the second surface of the wound portion and an electrode plate that is formed on the first surface so as not to be connected to the conductive layer. Since it is configured to be electrically connected, the capacity of the capacitor formed can be increased by interposing the insulating film and further the dielectric film between the two conductive layers of the portion that is entrained.
[0079]
  In addition, it is possible to provide a flexible double-sided printed circuit board in which a capacitor is formed on the board only by a configuration in which the end of the flexible double-sided printed circuit board is wound.
[0080]
  Furthermore, since the conductive layer on the second surface constituting one electrode of the capacitor is electrically connected to the electrode plate formed on the first surface, the connection terminals of both electrodes of the formed capacitor can be Can also be formed on the first surface, thereby simplifying the circuit pattern configuration. In addition, since the conductive layer on the second surface is bonded to the electrode plate on the first surface, a wide bonding surface can be secured, and flattening of the bonding surface can be facilitated, so that only the electrical characteristics of the bonded portion can be improved. A flexible double-sided printed circuit board with improved mechanical strength can be provided.
[0081]
  Claims of the invention2According to the method for forming a capacitor on a flexible double-sided printed circuit board, a flexible double-sided printed circuit board having conductive layers formed on both sides of a first surface and a second surface across a flexible insulating film having a predetermined dielectric constant is provided. The conductive layer on the first surface is covered with a dielectric film, the end portion is wound together with the dielectric film with the first surface inside, and the conductive layer on the second surface of the wound portion, the conductive layer on the first surface, Since the electrode plate formed in a non-connected manner is electrically connected, the capacitance of the formed capacitor can be increased by interposing an insulating film and further a dielectric film between the conductive layers of the part that is entrained. Can be increased.
[0082]
  In addition, the capacitor can be formed on the board only by the configuration in which the end of the flexible double-sided printed circuit board is wound.
[0083]
  Furthermore, by electrically connecting the conductive layer on the second surface constituting one electrode of the capacitor to the electrode plate formed on the first surface, the connection terminals of both electrodes of the formed capacitor are both connected to the first electrode. Therefore, the circuit pattern configuration can be simplified. In addition, by joining the conductive layer on the second surface to the electrode plate on the first surface, a wide joint surface can be secured, and flattening of the joint surface facilitates not only improving the electrical characteristics of the joint portion. Improvement of mechanical strength can be realized.
[Brief description of the drawings]
FIG. 1 of the present inventionReference exampleIt is a schematic cross section of the flexible double-sided printed circuit board concerning.
2 is a schematic cross-sectional view showing a process of a connecting method of the flexible double-sided printed circuit board shown in FIG.
3 is a schematic cross-sectional view showing a step that follows FIG. 2. FIG.
FIG. 4 shows the first aspect of the present invention.1It is a schematic cross section of a flexible double-sided printed circuit board provided with a capacitor according to an embodiment.
FIG. 5 is an explanatory diagram of capacitance formation of a flexible double-sided printed circuit board provided with the capacitor shown in FIG.
FIG. 6 of the present inventionOther reference examplesIt is a top view which shows the process of the connection method of the flexible double-sided printed circuit board concerning this.
7 is a side view of FIG. 6. FIG.
8 is a plan view showing a step that follows the step shown in FIG. 6. FIG.
9 is a side view of FIG. 8. FIG.
10 is a plan view showing a step that follows the step shown in FIG. 8. FIG.
FIG. 11 is a cross-sectional view of a conventional flexible double-sided printed circuit board.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Flexible double-sided printed circuit board, 2 ... Base film, 3 ... Circuit pattern, 3a ... Connection part, 6 ... 1st pattern electrode, 7 ... 2nd pattern electrode, 8 ... Conductive material, R1 …… First folding part, R2 …… Second folding part

Claims (3)

A flexible double-sided printed circuit in which conductive layers are formed on both the first surface and the second surface with an insulating film having flexibility and a predetermined dielectric constant ε1 interposed therebetween,
On the first surface of the flexible double-sided printed circuit board, an electrode plate is formed not connected to the conductive layer,
The conductive layer on the first surface of the flexible double-sided printed circuit board is covered with a dielectric film having a predetermined dielectric constant ε2 .
The end of the flexible double-sided printed circuit board is wound with the dielectric film and the first surface inside ,
The conductive layer on the second surface of the part that is wound is electrically connected to the electrode plate formed on the first surface ,
A flexible double-sided printed circuit board having a capacitor, wherein a capacitor having a dielectric constant ε1 and a capacitor having ε2 are formed between the conductive layer on the first surface and the conductive layer on the second surface . The flexible double-sided printed circuit board having a capacitor according to claim 1, wherein the capacitor having a dielectric constant ε1 and the capacitor having ε2 are connected in parallel. In this method, a capacitor is formed on a flexible double-sided printed circuit board in which conductive layers are formed on both the first surface and the second surface with an insulating film having flexibility and a predetermined dielectric constant ε1 interposed therebetween. And
On the first surface of the flexible double-sided printed circuit board, an electrode plate is formed so as not to be connected to the conductive layer of the first surface;
Covering the conductive layer on the first surface of the flexible double-sided printed circuit board with a dielectric film having a predetermined dielectric constant ε2 ,
The flexible double-sided printed circuit board is wound with the dielectric film and the first surface inside, along with the dielectric film,
Electrically connecting the conductive layer on the second surface of the wound portion and the electrode plate formed on the first surface so as to form a capacitor having a dielectric constant ε1 and a capacitor having a dielectric constant ε2. A method of forming a capacitor of a flexible double-sided printed circuit board, characterized in that

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