WO2017212966A1 - Flexible printed board - Google Patents

Flexible printed board Download PDF

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Publication number
WO2017212966A1
WO2017212966A1 PCT/JP2017/019859 JP2017019859W WO2017212966A1 WO 2017212966 A1 WO2017212966 A1 WO 2017212966A1 JP 2017019859 W JP2017019859 W JP 2017019859W WO 2017212966 A1 WO2017212966 A1 WO 2017212966A1
Authority
WO
WIPO (PCT)
Prior art keywords
power supply
circuit
conductor
supply circuit
flexible printed
Prior art date
Application number
PCT/JP2017/019859
Other languages
French (fr)
Japanese (ja)
Inventor
巧弥 長峯
北村 洋一
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to JP2018522427A priority Critical patent/JP6563129B2/en
Priority to GB1816765.0A priority patent/GB2565453B/en
Publication of WO2017212966A1 publication Critical patent/WO2017212966A1/en

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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0263High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board
    • H05K1/0265High current adaptations, e.g. printed high current conductors or using auxiliary non-printed means; Fine and coarse circuit patterns on one circuit board characterized by the lay-out of or details of the printed conductors, e.g. reinforced conductors, redundant conductors, conductors having different cross-sections
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/03Use of materials for the substrate
    • H05K1/0393Flexible materials
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0216Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0216Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • H05K1/0219Printed shielding conductors for shielding around or between signal conductors, e.g. coplanar or coaxial printed shielding conductors
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0213Electrical arrangements not otherwise provided for
    • H05K1/0216Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • H05K1/0224Patterned shielding planes, ground planes or power planes
    • H05K1/0227Split or nearly split shielding or ground planes
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0296Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295
    • H05K1/0298Multilayer circuits
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/0277Bendability or stretchability details
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/01Dielectrics
    • H05K2201/0137Materials
    • H05K2201/0154Polyimide
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09209Shape and layout details of conductors
    • H05K2201/09218Conductive traces
    • H05K2201/09227Layout details of a plurality of traces, e.g. escape layout for Ball Grid Array [BGA] mounting
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09209Shape and layout details of conductors
    • H05K2201/09218Conductive traces
    • H05K2201/09236Parallel layout
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09209Shape and layout details of conductors
    • H05K2201/095Conductive through-holes or vias
    • H05K2201/09618Via fence, i.e. one-dimensional array of vias
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09209Shape and layout details of conductors
    • H05K2201/09654Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09781Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09Shape and layout
    • H05K2201/09209Shape and layout details of conductors
    • H05K2201/09654Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/0979Redundant conductors or connections, i.e. more than one current path between two points
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/36Assembling printed circuits with other printed circuits
    • H05K3/361Assembling flexible printed circuits with other printed circuits

Definitions

  • the present invention relates to a flexible printed circuit board.
  • Wireless communication devices that transmit or receive radio waves via an antenna are roughly divided into an antenna, a high-frequency circuit, a control circuit, and a power supply circuit.
  • the antenna converts high-frequency electrical signals into radio waves.
  • the high frequency circuit is responsible for amplification, modulation and demodulation of the high frequency electric signal.
  • the control circuit supplies an electrical signal for controlling the high-frequency circuit.
  • the power supply circuit drives the high frequency circuit.
  • these electronic circuits are mounted on a printed circuit board for use.
  • the printed circuit board is composed of an IC (Integrated Circuit), individual electronic components, and metal conductors connecting them.
  • IC Integrated Circuit
  • the high-frequency circuit, the control circuit, and the power supply circuit are commonly mounted on a single printed circuit board.
  • these circuits are often mounted and used on separate printed circuit boards from the viewpoint of circuit noise countermeasures.
  • connection wiring for electrically connecting printed circuit boards on which these circuits are mounted is necessary.
  • connection wiring generally, a wiring component that bundles a plurality of electric wires called a wire harness and a connector for the wire harness are used.
  • the flexible printed board is a board made of a flexible insulator and metal conductor.
  • a flexible printed circuit board has a property of being thin and not bulky, lightweight and bendable. For this reason, the flexible printed circuit board is widely adopted for flat panel displays or small electronic devices.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2003-133660. This publication describes that a part of an insulating layer in which a plurality of signal lines constituting a signal circuit part is formed is cut out, and a power supply circuit part is attached to the cut out part.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a flexible printed circuit board having a plurality of electric circuits with different specifications and having high density, high accuracy, and low cost. is there.
  • the flexible printed board of the present invention includes a base film, a plurality of first conductors, a plurality of second conductors, and a plurality of connection conductors.
  • the base film has a first surface and a second surface facing each other, and is made of an insulator.
  • the plurality of first conductors are formed on the first surface of the base film.
  • the plurality of second conductors are formed on the second surface of the base film.
  • the plurality of connection conductors penetrate the base film and electrically connect a part of the plurality of first conductors and a part of the plurality of second conductors.
  • Each of the plurality of second conductors is thicker than each of the plurality of first conductors.
  • each of the plurality of second conductors is thicker than each of the plurality of first conductors. Therefore, an electric circuit that requires a thin film thickness can be formed with the first conductor, and an electric circuit that requires a thick film thickness can be formed with the second conductor. Accordingly, when a single flexible printed circuit board in which a plurality of electrical circuits that require different specifications are mixed is produced, a process that separately manufactures and bonds circuits that require different specifications is not necessary. Therefore, it is possible to realize a flexible printed board with high density, high accuracy, and low manufacturing cost.
  • FIG. 3 is a cross-sectional view showing the configuration of the flexible printed circuit board according to Embodiment 1 of the present invention, and is a cross-sectional view taken along the line II in FIGS. It is a top view which shows the structure of the flexible printed circuit board in Embodiment 1 of this invention. It is a rear view which shows the structure of the flexible printed circuit board in Embodiment 1 of this invention.
  • FIG. 7 is a cross-sectional view showing a configuration of a flexible printed circuit board in Embodiment 2 of the present invention, and is a cross-sectional view taken along line IV-IV in FIGS. 5 and 6. It is a top view which shows the structure of the flexible printed circuit board in Embodiment 2 of this invention.
  • FIG. 11 is a cross-sectional view showing a configuration of a flexible printed circuit board according to Embodiment 3 of the present invention, and is a cross-sectional view taken along line VII-VII in FIGS. 9 and 10.
  • FIG. 11 is a cross-sectional view showing a configuration of a flexible printed circuit board according to Embodiment 3 of the present invention, and is a cross-sectional view taken along the line VIII-VIII in FIGS. 9 and 10. It is a top view which shows the structure of the flexible printed circuit board in Embodiment 3 of this invention.
  • Embodiment 1 The configuration of flexible printed circuit board 100 according to Embodiment 1 of the present invention will be described with reference to FIGS.
  • the flexible printed circuit board 100 of the present embodiment includes a base film 1, a plurality of first conductors 2, 4, 6, 8, a plurality of second conductors 3, 7, 9, It mainly has a connection conductor 5.
  • the base film 1 has a main surface (first surface) 1a and a back surface (second surface) 1b facing each other, and is made of an insulator.
  • the base film 1 has a plurality of electric circuit forming regions having different specifications.
  • the plurality of electric circuit formation regions include, for example, a high frequency circuit unit 20, a power supply circuit unit 30, and a control circuit unit 40.
  • Each of the plurality of first conductors 2, 4, 6, 8 is formed on the main surface 1 a of the base film 1.
  • the plurality of first conductors 2, 4, 6, 8 include, for example, a center conductor 2, a ground conductor 4, a power supply circuit 6, and a control signal circuit 8.
  • Each of the plurality of second conductors 3, 7, 9 is formed on the back surface 1 b of the base film 1.
  • the plurality of second conductors 3, 7, 9 have, for example, a back ground conductor 3, an auxiliary power supply circuit 7, and a dummy circuit 9.
  • connection conductors 5 penetrates the base film 1, and electrically connects a part of the plurality of first conductors 2, 4, 6, 8 and a part of the plurality of second conductors 3, 7, 9. Connected to.
  • a through hole 5a is formed in the base film 1, and a connection conductor 5 is embedded in the through hole 5a.
  • the through hole 5a may penetrate not only the base film 1 but also each of the first conductor and the second conductor. In this case, the connection conductor 5 embedded in the through hole 5a also passes through the first conductor and the second conductor.
  • the plurality of connection conductors 5 include a high-frequency circuit connection conductor 5 formed in the high-frequency circuit unit 20 and a power supply circuit connection conductor 5 formed in the power supply circuit unit 30.
  • the film thickness T1 of each of the plurality of second conductors 3, 7, 9 is set to be thicker than the film thickness T2 of each of the plurality of first conductors 2, 4, 6, 8.
  • the base film 1 for example, a polymer film having excellent flexibility and heat resistance, such as a polyimide film having a thickness of 12.5 ⁇ m to 50 ⁇ m, and a low dielectric loss can be used.
  • a polymer film having excellent flexibility and heat resistance such as a polyimide film having a thickness of 12.5 ⁇ m to 50 ⁇ m, and a low dielectric loss can be used.
  • Each of the plurality of thin first conductors 2, 4, 6, 8 is composed of, for example, a copper thin film (copper foil), a nickel thin film, and a gold thin film.
  • the copper foil is formed on the main surface 1a of the base film 1, and has a film thickness of, for example, 6 ⁇ m or more and 18 ⁇ m or less.
  • the nickel thin film is formed on the surface of the copper foil, and has a film thickness of, for example, 3 ⁇ m or more and 5 ⁇ m or less.
  • the gold thin film is formed on the surface of the nickel thin film, and has a thickness of about 0.01 ⁇ m, for example.
  • the nickel thin film and the gold thin film on the surface of the copper foil are formed for the purpose of preventing oxidation of the thin conductor layer and improving solder wettability.
  • Each of the thick plurality of second conductors 3, 7, 9 is composed of, for example, a copper foil, a nickel thin film, and a gold thin film.
  • the copper foil is formed on the back surface 1b of the base film 1, and has a film thickness of, for example, 18 ⁇ m or more and 70 ⁇ m or less.
  • the nickel thin film is formed on the surface of the copper foil, and has a film thickness of, for example, 3 ⁇ m or more and 5 ⁇ m or less.
  • the gold thin film is formed on the surface of the nickel thin film, and has a thickness of about 0.01 ⁇ m, for example. Similar to the first conductors 2, 4, 6, and 8, the nickel thin film and the gold thin film on the surface of the copper foil are formed for the purpose of preventing oxidation of the thin conductor layer and improving solder wettability.
  • the copper foil of each of the first conductors 2, 4, 6, 8 and the second conductors 3, 7, 9 and the polyimide film substrate of the base film 1 are made of an epoxy resin adhesive or an acrylic resin adhesive not shown. It is glued.
  • the copper foil and the polyimide base material may be connected to each other without using an adhesive, focusing on electric characteristics such as high-frequency characteristics.
  • the copper foil and the polyimide film substrate are formed by a method in which the copper foil is baked after being coated with the polyimide varnish, or a method in which a metal conductor layer is formed on the polyimide film substrate using sputtering and plating. May be connected.
  • the general flexible printed circuit board 100 is often provided with a protective film such as a component other than the above, for example, a solder resist or a coverlay.
  • a protective film such as a component other than the above, for example, a solder resist or a coverlay.
  • these protective films are members not related to the present invention, description thereof is omitted.
  • the base film 1 has, for example, a high-frequency circuit unit 20, a power circuit unit 30, and a control circuit unit 40 as regions for forming a plurality of electric circuits having different specifications. is doing.
  • Each of these electric circuit portions 20, 30, 40 includes a first conductor 2, 4, 6, 8 formed on the main surface 1a of the base film 1, and a second conductor 3, 7, formed on the back surface 1b. 9 is configured to function as a single unit so that the circuit function is exhibited.
  • the high-frequency circuit unit 20 will be described.
  • transmission lines made of two kinds of conductors are formed on the main surface 1 a of the base film 1. That is, on the main surface 1 a of the flexible printed circuit board 100, the center conductor 2 and a pair of ground conductors 4 located on both sides of the center conductor 2 are formed.
  • Each of the center conductor 2 and the pair of ground conductors 4 is a linear transmission line as shown in FIG.
  • the central conductor 2 and each of the pair of ground conductors 4 are arranged so that the longitudinal direction of the central conductor 2 and the longitudinal direction of each of the pair of ground conductors 4 are parallel to each other.
  • the back ground conductor 3 is formed on the back surface 1 b of the base film 1.
  • Each of the pair of ground conductors 4 is electrically connected to one back ground conductor 3 by a high-frequency circuit connection conductor 5 that fills the through hole 5a.
  • the minimum transmission line configuration is a combination of the center conductor 2 and the ground conductor 4, and a coplanar structure is obtained by this combination.
  • Another minimum transmission line configuration is a combination of the center conductor 2 and the back ground conductor 3, and a microstrip structure can be obtained by this combination.
  • the conductor dimensions, shape, and arrangement of the center conductor 2 are designed so that high-frequency signals can be transmitted most efficiently.
  • the conductor dimensions, shape, and arrangement of the center conductor 2 are such that the conductivity of the center conductor 2 that transmits signals and the base film 1 that separates the center conductor 2 (and the ground conductor 4) and the back ground conductor 3 from each other. What is necessary is just to obtain
  • the conductor thickness of the center conductor 2 may be reduced to such an extent that there is no problem in manufacturing and use. That is, the conductor thickness of the center conductor 2 may be made as thin as possible as long as it is not affected by the skin effect known as a phenomenon that causes an increase in circuit resistance in the center conductor 2. As a result, the side etching phenomenon that the cross-sectional shape of the central conductor 2 becomes trapezoid in the etching during patterning of the central conductor 2 is minimized. Thereby, it is possible to manufacture a substrate in which the shape of the conductor obtained by the electromagnetic field simulation is reproduced with high accuracy. Specifically, the conductor thickness is desirably in the range of 6 ⁇ m to 18 ⁇ m.
  • the conductor thickness of the conductor for the back ground conductor 3 is not necessary to reduce the thickness of the conductor for the back ground conductor 3.
  • the characteristic required for the back ground conductor 3 is only the function as the ground conductor. That is, the back ground conductor 3 only needs to function as a ground conductor only at the portion in contact with the back surface 1b side of the base film 1, and the conductor acts as a ground conductor even if the conductor thickness is thin or thick. To do. Specifically, there is no problem if the conductor thickness of the back ground conductor 3 is thicker than the center conductor 2 and about 70 ⁇ m or less.
  • the high-frequency circuit connection conductor 5 extends along the length direction of the flexible printed circuit board 100 (the extending direction of the ground conductor 4), and the center line of the ground conductor 4. It is arranged in the vicinity of a point sequence.
  • the high-frequency circuit connection conductor 5 electromagnetically functions as a ground conductor (shield wall).
  • the diameter of the high-frequency circuit connection conductor 5 is preferably 50 ⁇ m or more and 300 ⁇ m or less.
  • the power supply circuit unit 30 As shown in FIGS. 1 to 3, in the power supply circuit unit 30, the power supply circuit 6 is provided on the main surface 1 a of the base film 1. In the power circuit 30, an auxiliary power circuit 7 is provided on the back surface 1 b of the base film 1. The auxiliary power circuit 7 is disposed at a position facing the power circuit 6 with the base film 1 interposed.
  • the auxiliary power supply circuit 7 refers to a bypass circuit provided in association with the power supply circuit 6 in order to send a large current. That is, the thickness of the metal conductor of the auxiliary power circuit 7 is designed to be at least thicker than the power circuit 6, and a large current can be transmitted with the total current capacity of the power circuit 6 and the auxiliary power circuit 7. .
  • the power supply circuit 6 and the auxiliary power supply circuit 7 are electrically connected to each other by a power supply circuit connection conductor 5.
  • a plurality of power supply circuit connection conductors 5 can be provided to secure a current capacity to be described later.
  • the power supply circuit unit 30 is required to have a structure capable of supplying a large current in preparation for a case where power consumption of a circuit connected as a load is large.
  • the conductor thickness of the power supply circuit 6 is designed to be the same as the thickness of the first conductor formed on the main surface 1a, that is, the thickness of the conductor at which the center conductor 2 can transmit high frequency most efficiently. For this reason, the conductor thickness of the power supply circuit 6 cannot be increased in order to increase the current capacity. Further, the method of widening the power supply circuit 6 cannot be adopted from the viewpoint of miniaturization and space saving required for the flexible printed circuit board 100.
  • the auxiliary power circuit 7 is provided on the back surface 1b so as to face the power circuit 6 formed on the main surface 1a, and the power circuit 6 and the auxiliary power circuit 7 are connected to the power circuit connecting conductor. 5 is electrically connected.
  • the conductor width of the auxiliary power circuit 7 is equal to the conductor width of the power circuit 6. For this reason, even if the auxiliary power supply circuit 7 is provided, the width of the power supply circuit section 30 does not increase.
  • the auxiliary power circuit 7 is formed on the back surface 1b of the base film 1, there is no restriction on the manufacturing process that the same thickness as that of the central conductor 2 formed on the main surface 1a is required. Therefore, the auxiliary power supply circuit 7 can be formed with the same thick conductor thickness as that of the back ground conductor 3 without being restricted by the manufacturing process.
  • the cross-sectional area of the conductor necessary for energizing a large current can be secured by the combined cross-sectional area of the power supply circuit 6 and the auxiliary power supply circuit 7.
  • the number of power supply circuit connection conductors 5 in the power supply circuit unit 30 may be set based on the cross-sectional area of the auxiliary power supply circuit 7. That is, the cross-sectional area when the power supply circuit connection conductor 5 is cut and the integrated value of the number of the power supply circuit connection conductors 5 may be designed to be equal to or larger than the cross-sectional area of the auxiliary power supply circuit 7.
  • control circuit unit 40 As shown in FIGS. 1 to 3, the control signal circuit 8 is provided on the main surface 1 a of the base film 1 in the control circuit unit 40. In the control circuit unit 40, a dummy circuit 9 is provided on the back surface 1 b of the base film 1.
  • Each of the plurality of control signal circuits 8 is arranged so that the longitudinal directions of the plurality of control signal circuits 8 run parallel to each other. Further, each of the plurality of control signal circuits 8 and each of the plurality of power supply circuits 6 are arranged so that the longitudinal direction of each of the plurality of control signal circuits 8 and each longitudinal direction of the plurality of power supply circuits 6 run in parallel with each other. It is out.
  • the control signal circuit 8 is a digital circuit. For this reason, the control signal circuit 8 is different from the high-frequency circuit unit 20 of an analog circuit that is easily affected by noise or the power supply circuit unit 30 that has to examine the problem of heat generation, even if no special consideration is required in terms of electrical circuit. Can be operated. Therefore, the control signal circuits 8 can be arranged as densely as possible in terms of manufacturing.
  • Such high-density wiring is expressed in line and space.
  • the conductor width of the wiring is called a line
  • the interval between adjacent wirings is called a space.
  • the conductor thickness of the control signal circuit 8 is formed to be equal to the conductor thickness of the center conductor 2. Therefore, the conductor thickness of the control signal circuit 8 is designed in the range of 6 ⁇ m or more and 18 ⁇ m or less, which is a design guideline for the center conductor 2 thinned to the limit in manufacturing and use. Thereby, also in the control signal circuit 8, the side etching phenomenon is minimized.
  • the line and space of the control signal circuit 8 in the first embodiment is 50 ⁇ m (line) / 50 ⁇ m (space) to 150 ⁇ m (line) / 150 ⁇ m (space).
  • the dummy circuit 9 is a circuit having a conductor thickness equal to that of the circuit on the back surface 1 b other than the control circuit unit 40, that is, the back surface ground conductor 3 and the auxiliary power supply circuit 7.
  • the dummy circuit 9 allows the thickness in the control circuit unit 40 (the total of the thickness of the base film 1, the thickness of the control signal circuit 8 and the thickness of the dummy circuit 9) to be the thickness of the high-frequency circuit unit 20 (the thickness of the base film 1).
  • the thickness of the central conductor 2 and the thickness of the back ground conductor 3) and the thickness in the power supply circuit section 30 (the sum of the thickness of the base film 1, the power supply circuit 6, and the auxiliary power supply circuit 7). can do.
  • the dummy circuit 9 may be omitted if it is determined that it is not necessary to provide the dummy circuit 9 by considering the rigidity, thickness, and handling of the flexible printed circuit board 100 as a whole. Although the dummy circuit 9 in the flexible printed circuit board 100 is floating, when the control signal circuit 8 is easily affected by noise, it can be electrically connected to the ground conductor as necessary.
  • a form of electrically connecting printed boards using a flexible printed board includes the following connected forms.
  • a flexible printed circuit board connector has a metal terminal provided inside a flat resin connector. After the flexible printed board is inserted into the connector, the resin cover is closed. As a result, the terminals of the flexible printed circuit board are mechanically pressed against the terminals inside the connector, whereby the two are electrically connected.
  • the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, in the connection by the said connector, it is suppressed that a load becomes nonuniform between the terminal of the flexible printed circuit board 100, and the terminal inside a connector. As a result, poor conduction is unlikely to occur between the terminals of the flexible printed circuit board 100 and the terminals inside the connector, and a highly reliable connector connection is possible.
  • ACF anisotropic conductive adhesive film
  • flexible printed circuit board 100 and printed circuit board 200 in the present embodiment are connected using, for example, ACF.
  • the ACF includes conductive particles 12 having a diameter of several ⁇ m to several tens of ⁇ m in a resin 11 serving as a binder.
  • conductive particles 12 nickel particles or resin particles plated with metal are often used.
  • the conductive particles 12 of ACF are sandwiched between the pad electrodes 202, 204, 206, 208 on the printed circuit board 200 and the terminals 2, 4, 6, 8 of the flexible printed circuit board 100.
  • a proper load is applied.
  • electrical conduction is obtained between the pad electrodes 202, 204, 206, 208 of the printed circuit board 200 and the terminals 2, 4, 6, 8 of the flexible printed circuit board 100.
  • the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, a load necessary for capturing the conductive particles 12 of ACF is evenly applied in the plane of the flexible printed circuit board 100. Thereby, since it becomes possible to pinch
  • electrical_connection can be obtained.
  • connection using solder will be described. If there is a step on the surface of the conductor in the surface of the flexible printed circuit board, there is a possibility that a conductor that contacts the molten solder and a conductor that does not contact may come out during soldering. .
  • the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, highly reliable conduction can be obtained without problems even in solder.
  • the characteristic impedance of the flexible printed circuit board is determined by the thickness of the substrate material, the dielectric constant of the substrate material, the thickness of the metal conductor, and the width of the metal conductor. For this reason, it is possible to match the characteristic impedance by properly designing them and manufacturing the substrate with high accuracy.
  • the thickness of each of the plurality of second conductors 3, 7, 9 is the same as that of each of the plurality of first conductors 2, 4, 6, 8. Thicker than film thickness. Therefore, an electric circuit that requires a thin film thickness can be formed with the first conductor, and an electric circuit that requires a thick film thickness can be formed with the second conductor.
  • the thickness of the central conductor 2 can be reduced to a level that does not cause a problem in manufacturing and use. Thereby, the side etching phenomenon that the cross-sectional shape of the center conductor 2 becomes trapezoid in the etching at the time of patterning of the center conductor 2 is minimized. Thereby, the board
  • the auxiliary power circuit 7 is formed on the back surface 1b in the power circuit section 30, there is no manufacturing process restriction that the thickness must be the same as that of the center conductor 2 formed on the main surface 1a. Therefore, the auxiliary power supply circuit 7 can be formed with the same thick conductor thickness as that of the back ground conductor 3 without being restricted by the manufacturing process. As a result, the cross-sectional area of the conductor necessary for energizing a large current can be obtained by the cross-sectional area of the auxiliary power supply circuit 7. Thereby, since the subject that the cross-sectional area of the conductor mentioned above is insufficient can be solved, the degree of freedom in design can be greatly improved.
  • the conductor thickness of the control signal circuit 8 can be reduced to the extent that there is no problem in manufacturing and use, like the central conductor 2.
  • the side etching phenomenon that the cross-sectional shape of the control signal circuit 8 becomes trapezoid in the etching during patterning of the control signal circuit 8 is minimized.
  • the control signal circuits 8 can be arranged with high density.
  • a plurality of electrical circuit units 20, 30, 40 that require different specifications can be formed on one flexible printed circuit board 100 while satisfying different specifications of the plurality of electrical circuit units 20, 30, 40. it can. This eliminates the need for separately manufacturing and bonding a plurality of electrical circuits that require different specifications. Therefore, it is possible to realize a flexible printed board with high density, high accuracy, and low manufacturing cost.
  • a protective layer 13a may be provided on the main surface 1a of the flexible printed circuit board 100, and a protective layer 13b may be provided on the back surface 1b.
  • a flexible film such as polyimide or a photosensitive resin such as a solder resist can be used.
  • Each of the protective layers 13a and 13b is bonded and fixed to each of the main surface 1a and the back surface 1b of the flexible printed circuit board 100 with an adhesive (not shown) to protect the conductor surface from corrosion and oxidation. Thereby, environmental resistance can be improved.
  • the protective layers 13a and 13b When the protective layers 13a and 13b are provided, it is necessary to design the protective layers 13a and 13b so as not to affect the electrical connection with the printed circuit board 200 on the main surface 1a and the back surface 1b. For example, when conductive particles having a diameter of several ⁇ m to several tens of ⁇ m are sandwiched between wirings, such as ACF, it is necessary to design the protective layer 13a so as not to prevent the capturing of the conductive particles between the wirings. .
  • FIG. As shown in FIGS. 4 to 6, the flexible printed circuit board 100 according to the second embodiment is replaced with the power supply circuit unit 30, the control circuit unit 40, and the power supply circuit unit 30 and the control circuit unit 40 according to the first embodiment. Is different from the configuration of the first embodiment in that it has a composite circuit unit 50 in which is combined.
  • the composite circuit unit 50 is a circuit unit in which the power supply circuit unit 30 and the control circuit unit 40 are combined, and includes the power supply circuit 6, the auxiliary power supply circuit 7, the control signal circuit 8, and the power supply circuit connection conductor 5. Have.
  • the auxiliary power circuit 7 is formed on the back surface 1 b so as to face not only the power circuit 6 but also the control signal circuit 8. That is, the dummy circuit 9 in the first embodiment is omitted, and the conductor width of the auxiliary power circuit 7 is extended to the back side of the control signal circuit 8.
  • the auxiliary power circuit 7 is electrically connected to the power circuit 6 by a power circuit connecting conductor 5 that fills the through hole 5a.
  • the dummy circuit 9 is omitted, and the conductor width of the auxiliary power circuit 7 is extended to the back side of the control signal circuit 8.
  • the auxiliary power circuit 7 can have a larger cross-sectional area than that of the first embodiment.
  • the temperature rise of the wiring related to the power supply circuit is caused by heat generation due to Joule heat caused by the current value and resistance value of the circuit.
  • the temperature of the member constituting the circuit depends on the environment in which the member is placed, that is, the outside air temperature around the member and the heat dissipation, and therefore varies depending on the part. Since the heat escapes quickly in the part with good heat dissipation of the circuit, the temperature is kept low. On the other hand, the temperature of the portion where the heat dissipation property of the circuit is bad increases because heat accumulates.
  • the heat generated by the flexible printed circuit board is quickly radiated to a metal casing or the like outside the printed circuit board through a metal part such as a pad electrode or a through hole of the printed circuit board.
  • a metal part such as a pad electrode or a through hole of the printed circuit board.
  • the periphery of the flexible printed circuit board is air which is a thermal insulator.
  • the members constituting the flexible printed circuit board are composed of the polyimide film base and the epoxy resin adhesive or the acrylic resin adhesive as described above except for the metal wiring portion, the thermal conductivity is significantly low (both Both are about 0.2W / mK).
  • the generation of Joule heat is suppressed by increasing the cross-sectional area of the auxiliary power circuit 7. Further, by increasing the surface area of the auxiliary power circuit 7 and causing the auxiliary power circuit 7 to function as a heat sink, heat dissipation into the air is facilitated. Thereby, the temperature rise of the whole flexible printed circuit board 100 is reduced.
  • the conductor width of the power supply circuit 6 only needs to have a minimum width necessary to connect the power supply circuit connection conductor 5. Further, the power supply circuit 6 can increase the connection area with the printed circuit board in the longitudinal direction of the power supply circuit 6 if necessary, so that the high-density wiring area of the control signal circuit 8 is not hindered.
  • the flexible printed circuit board 100 in the present embodiment has a uniform thickness in the plane of the flexible printed circuit board 100 as in the cross-sectional structure of the flexible printed circuit board 100 shown in FIG. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.
  • the flexible printed circuit board 100 in the present embodiment is a composite in which a power supply circuit unit 30 and a control circuit unit 40 are combined instead of the control circuit unit 40 in the first embodiment.
  • the configuration differs from that of the first embodiment in that the circuit portion 60 is provided.
  • a plurality of control signal circuits 8 and a plurality of power circuit terminals 10 are formed on the main surface 1 a of the base film 1.
  • the auxiliary power circuit 7 is formed on the back surface 1 b of the base film 1.
  • the plurality of control signal circuits 8 linearly extend on the main surface 1a so that the longitudinal directions of the plurality of control signal circuits 8 run in parallel with each other.
  • the plurality of power supply circuit terminals 10 are located on an extension line in the longitudinal direction of the control signal circuit 8 on the main surface 1a, and are arranged on both one side and the other side in the longitudinal direction of the control signal circuit 8. .
  • the plurality of auxiliary power supply circuits 7 in the composite circuit unit 60 extend linearly so as to run parallel to each other on the back surface 1b.
  • Each of the plurality of power supply circuits 6 is electrically connected to the auxiliary power supply circuit 7 by a power supply circuit connection conductor 5.
  • Each of the plurality of power supply circuit connection conductors 5 is formed so as to embed a through hole 5a formed in the base film 1.
  • the composite circuit section 60 is provided when the current capacity of the power supply circuit section 30 is insufficient with respect to the current capacity required for the flexible printed circuit board 100. Also in the present embodiment, the power supply circuit unit 30 bears most of the current capacity of the flexible printed circuit board 100. However, the current capacity of the power supply circuit unit 30 can be supplementarily increased by the additional structure provided in the composite circuit unit 60.
  • the configuration of the present embodiment is a structure that is purely intended to increase the contact area of the connection portion.
  • connection configuration that requires such a structure is caused by Joule heat generated at the connection portion when the resistance of the connection portion rises to about several ⁇ when a circuit is connected using, for example, ACF, and a large current is applied. Effective when heat generation cannot be ignored. Moreover, the connection form which requires such a structure is effective even in an analog circuit in which a problem occurs in a circuit unless the connection portion is connected with low impedance.
  • FIG. A dotted line in FIG. 11 represents a portion where the flexible printed circuit board 100 overlaps the printed circuit board 200 when the flexible printed circuit board 100 and the printed circuit board 200 are connected.
  • the printed circuit board 200 includes a substrate 201, a center conductor 202, a ground conductor 204, a power supply circuit 206, a control circuit terminal 208, a power supply circuit terminal 210, and a lower layer wiring 215. It mainly has a conductor 205.
  • the substrate 201 has a plurality of electric circuit formation regions having different specifications.
  • the plurality of electric circuit formation regions include, for example, a high-frequency circuit unit 220, a power supply circuit unit 230, and a composite circuit unit 260.
  • a center conductor 202 and a ground conductor 204 are formed on the surface of the substrate 201.
  • two ground conductors 204 sandwich one central conductor 202.
  • the center conductor 202 and the two ground conductors 204 extend linearly so as to run in parallel with each other.
  • a plurality of power supply circuits 206 are formed on the surface of the substrate 201. Each of the plurality of power supply circuits 206 extends linearly so as to run in parallel with each other. Each of the plurality of power supply circuits 206 is parallel to the center conductor 202 and the ground conductor 204.
  • a plurality of control circuit terminals 208 and a plurality of power supply circuit terminals 210 are formed on the surface of the substrate 201.
  • the plurality of control circuit terminals 208 are arranged side by side in the same direction as the direction in which the plurality of power supply circuits 206 are arranged.
  • the plurality of power supply circuit terminals 210 are arranged side by side in the same direction as the direction in which the plurality of power supply circuits 206 are arranged.
  • Each of the plurality of power supply circuit terminals 210 is electrically connected to each of the power supply circuits 206 by a lower layer wiring 215.
  • Each of the plurality of lower layer wirings 215 extends from the power supply circuit unit 230 to the composite circuit unit 260 on the back surface of the substrate 201.
  • the lower layer wiring 215 is electrically connected to the power supply circuit 206 by the connection conductor 205.
  • the lower layer wiring 215 is electrically connected to the power supply circuit terminal 210 by the connection conductor 205.
  • the control circuit terminal 208 is electrically connected to a lower layer wiring (not shown) formed on the back surface of the substrate 201 by a connection conductor 205.
  • connection conductor 205 is formed so as to be embedded in the through hole 205a provided in the substrate 201.
  • the power supply circuit 6 (FIG. 9) is electrically connected by sandwiching conductive particles of ACF between the power supply circuit 206 (FIG. 11) facing the power supply circuit 6 (FIG. 9).
  • the widths of the flexible printed circuit board 100 and the printed circuit board 200 are increased, which is a factor that hinders downsizing of the entire product.
  • the flexible printed circuit board 100 is provided with a composite circuit portion 60, and the printed circuit board 200 corresponds to the pattern of the main surface 1 a of the composite circuit portion 60 as shown in FIG. 11.
  • a control circuit terminal 208 and a power circuit terminal 210 are provided.
  • the power supply circuit terminal 210 is electrically connected to the lower layer wiring 215 by the connection conductor 205, and the lower layer wiring 215 is electrically connected to the power supply circuit 206 by the connection conductor 205.
  • the power supply circuit terminal 210 is electrically connected to the power supply circuit 206.
  • the control circuit terminal 208 is also wired in the plane of the printed circuit board 200 by the connection conductor 205 and a lower layer wiring (not shown).
  • the current flowing through the power supply circuit 206 of the printed circuit board 200 is divided into the following two paths. That is, a path for energizing the composite circuit unit 60 of the flexible printed circuit board 100 through the connection conductor 205, the lower layer wiring 215, and the power circuit terminal 210, and a power circuit 206 for the printed circuit board 200 and the power circuit unit 30 of the flexible printed circuit board 100 are energized. It is a route.
  • the flexible printed circuit board 100 according to the present embodiment can increase the area of the ACF connection portion, the resistance of the connection portion can be reduced.
  • the power supply circuit 6 of the power supply circuit unit 30 on the main surface 1a can be used as a redundant circuit even when conduction failure occurs for some reason. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.
  • the flexible printed circuit board 100 in the present embodiment has a uniform thickness in the surface of the flexible printed circuit board as in the cross-sectional structure of the flexible printed circuit board 100 shown in FIG. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Structure Of Printed Boards (AREA)
  • Combinations Of Printed Boards (AREA)

Abstract

According to the present invention, a base film (1) has a main surface (1a) and a back surface (1b), which are on opposite sides of each other, and is formed from an insulating material. A plurality of first conductors (2, 4, 6, 8) are formed on the main surface (1a) of the base film (1). A plurality of second conductors (3, 7, 9) are formed on the back surface (1b) of the base film (1). A plurality of connection conductors (5) penetrate through the base film (1) and electrically connect some of the first conductors (2, 4, 6, 8) and some of the second conductors (3, 7, 9) with each other. The film thicknesses of the plurality of second conductors (3, 7, 9) are thicker than the film thicknesses of the plurality of first conductors (2, 4, 6, 8).

Description

フレキシブルプリント基板Flexible printed circuit board
 本発明は、フレキシブルプリント基板に関するものである。 The present invention relates to a flexible printed circuit board.
 空中線を介して電波を発信または受信する無線通信機器は、大別して、アンテナと、高周波回路と、制御回路と、電源回路とにより構成される。アンテナは、高周波の電気信号を電波に変換する。高周波回路は、高周波電気信号の増幅および変調・復調を担う。制御回路は、上記高周波回路を制御するための電気信号を供給する。電源回路は、上記高周波回路を駆動する。 Wireless communication devices that transmit or receive radio waves via an antenna are roughly divided into an antenna, a high-frequency circuit, a control circuit, and a power supply circuit. The antenna converts high-frequency electrical signals into radio waves. The high frequency circuit is responsible for amplification, modulation and demodulation of the high frequency electric signal. The control circuit supplies an electrical signal for controlling the high-frequency circuit. The power supply circuit drives the high frequency circuit.
 一般にこれらの電子回路は、プリント基板に搭載されて使用に供される。プリント基板は、IC(Integrated Circuit)、個別の電子部品、それらを接続する金属導体などで構成される。上記高周波回路、制御回路および電源回路が単一のプリント基板上に共通で実装される事例もある。しかし、これらの回路は、回路のノイズ対策などの観点から、それぞれ別個のプリント基板上に実装されて用いられることが多い。 Generally, these electronic circuits are mounted on a printed circuit board for use. The printed circuit board is composed of an IC (Integrated Circuit), individual electronic components, and metal conductors connecting them. In some cases, the high-frequency circuit, the control circuit, and the power supply circuit are commonly mounted on a single printed circuit board. However, these circuits are often mounted and used on separate printed circuit boards from the viewpoint of circuit noise countermeasures.
 後者の場合、これらの回路を実装したプリント基板間を電気的に接続する接続配線が必要である。上記接続配線には、一般に、ワイヤーハーネスと呼ばれる複数の電線を束にした配線部品と、ワイヤーハーネス用のコネクタとが用いられる。 In the latter case, connection wiring for electrically connecting printed circuit boards on which these circuits are mounted is necessary. For the connection wiring, generally, a wiring component that bundles a plurality of electric wires called a wire harness and a connector for the wire harness are used.
 近年、高品位な情報通信を広く普及させるために、通信機器の小型化、薄型化が求められている。しかし、上記ワイヤーハーネスとワイヤーハーネス用コネクタとの併用には、通信機器自体の大型化および重量の増加といった問題がある。そこで通信機器の小型化、薄型化の要求を満たすために、上記接続配線にフレキシブルプリント基板を用いることが考えられる。 In recent years, in order to widely disseminate high-quality information communication, there has been a demand for smaller and thinner communication devices. However, the combined use of the wire harness and the wire harness connector has problems such as an increase in size and weight of the communication device itself. Therefore, in order to satisfy the demands for reducing the size and thickness of communication devices, it is conceivable to use a flexible printed circuit board for the connection wiring.
 フレキシブルプリント基板は、柔軟性をもった絶縁体と金属導体から成る基板である。フレキシブルプリント基板は、薄型で嵩張らず、軽量で折り曲げ可能といった性質を有する。このためフレキシブルプリント基板は、フラットパネルディスプレイまたは小型の電子デバイスに広く採用されている。 The flexible printed board is a board made of a flexible insulator and metal conductor. A flexible printed circuit board has a property of being thin and not bulky, lightweight and bendable. For this reason, the flexible printed circuit board is widely adopted for flat panel displays or small electronic devices.
 このようなフレキシブルプリント基板は、たとえば特開2003-133660号公報(特許文献1)に開示されている。この公報には、信号回路部分を構成する複数の信号線が形成された絶縁層の一部を切り抜き、その切り抜いた箇所に電源回路部分を張り合わせることが記載されている。 Such a flexible printed circuit board is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-133660 (Patent Document 1). This publication describes that a part of an insulating layer in which a plurality of signal lines constituting a signal circuit part is formed is cut out, and a power supply circuit part is attached to the cut out part.
特開2003-133660号公報JP 2003-133660 A
 しかし、上記公報に記載のフレキシブルプリント基板においては、別個に用意した回路を貼り合わせる工程で、貼り合わせる回路同士での位置ずれが少なからず発生する。回路同士の位置がずれると接続不具合が発生するため、回路を高密度にできないという問題がある。 However, in the flexible printed circuit board described in the above publication, in the process of laminating separately prepared circuits, misalignment between the circuits to be bonded occurs. If the positions of the circuits are shifted, a connection failure occurs, so that there is a problem that the circuits cannot be made dense.
 また貼り合わせによって別個の部品を一体化しようとすると、接着剤のはみ出し、接着工程中に発生するフレキシブルプリント基板の歪みまたは変形などの懸念も増大する。 Further, when trying to integrate separate parts by bonding, there is an increased concern about the protrusion of the adhesive and distortion or deformation of the flexible printed circuit board that occurs during the bonding process.
 また、適用する回路毎に別個に絶縁体を用意して回路を形成し、さらにそれらを貼り合わせる工程が必要となる。そのため、製造工程数と製造コストが増大するという問題がある。 Also, it is necessary to prepare a separate insulator for each circuit to be applied, form a circuit, and further bond them together. Therefore, there exists a problem that the number of manufacturing processes and manufacturing cost increase.
 本発明は、上記の課題に鑑みてなされたものであり、その目的は、互いに異なる仕様の複数の電気回路を有し、かつ高密度、高精度および低コストなフレキシブルプリント基板を提供することである。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a flexible printed circuit board having a plurality of electric circuits with different specifications and having high density, high accuracy, and low cost. is there.
 本発明のフレキシブルプリント基板は、ベースフィルムと、複数の第1導体と、複数の第2導体と、複数の接続導体とを備えている。ベースフィルムは、互いに対向する第1面および第2面を有し、かつ絶縁体よりなっている。複数の第1導体は、ベースフィルムの第1面に形成されている。複数の第2導体は、ベースフィルムの第2面に形成されている。複数の接続導体は、ベースフィルムを貫通し、かつ複数の第1導体の一部と複数の第2導体の一部とを電気的に接続している。複数の第2導体の各々の膜厚は複数の第1導体の各々の膜厚よりも厚い。 The flexible printed board of the present invention includes a base film, a plurality of first conductors, a plurality of second conductors, and a plurality of connection conductors. The base film has a first surface and a second surface facing each other, and is made of an insulator. The plurality of first conductors are formed on the first surface of the base film. The plurality of second conductors are formed on the second surface of the base film. The plurality of connection conductors penetrate the base film and electrically connect a part of the plurality of first conductors and a part of the plurality of second conductors. Each of the plurality of second conductors is thicker than each of the plurality of first conductors.
 以上説明したように本発明によれば、複数の第2導体の各々の膜厚は複数の第1導体の各々の膜厚よりも厚い。このため薄い膜厚が必要な電気回路は第1導体で形成し、かつ厚い膜厚が必要な電気回路は第2導体で形成することができる。これにより、互いに異なる仕様を必要とする複数の電気回路を混在させた一枚のフレキシブルプリント基板を製作する場合に、異なる仕様を必要とする回路を別個に製作して貼り合わせる工程が必要なくなる。よって、高密度で高精度かつ製造コストを低く抑えたフレキシブルプリント基板を実現することが可能となる。 As described above, according to the present invention, each of the plurality of second conductors is thicker than each of the plurality of first conductors. Therefore, an electric circuit that requires a thin film thickness can be formed with the first conductor, and an electric circuit that requires a thick film thickness can be formed with the second conductor. Accordingly, when a single flexible printed circuit board in which a plurality of electrical circuits that require different specifications are mixed is produced, a process that separately manufactures and bonds circuits that require different specifications is not necessary. Therefore, it is possible to realize a flexible printed board with high density, high accuracy, and low manufacturing cost.
本発明の実施の形態1におけるフレキシブルプリント基板の構成を示す断面図であり、図2、図3のI-I線に沿う断面図である。FIG. 3 is a cross-sectional view showing the configuration of the flexible printed circuit board according to Embodiment 1 of the present invention, and is a cross-sectional view taken along the line II in FIGS. 本発明の実施の形態1におけるフレキシブルプリント基板の構成を示す平面図である。It is a top view which shows the structure of the flexible printed circuit board in Embodiment 1 of this invention. 本発明の実施の形態1におけるフレキシブルプリント基板の構成を示す背面図である。It is a rear view which shows the structure of the flexible printed circuit board in Embodiment 1 of this invention. 本発明の実施の形態2におけるフレキシブルプリント基板の構成を示す断面図であり、図5、図6のIV-IV線に沿う断面図である。FIG. 7 is a cross-sectional view showing a configuration of a flexible printed circuit board in Embodiment 2 of the present invention, and is a cross-sectional view taken along line IV-IV in FIGS. 5 and 6. 本発明の実施の形態2におけるフレキシブルプリント基板の構成を示す平面図である。It is a top view which shows the structure of the flexible printed circuit board in Embodiment 2 of this invention. 本発明の実施の形態2におけるフレキシブルプリント基板の構成を示す背面図である。It is a rear view which shows the structure of the flexible printed circuit board in Embodiment 2 of this invention. 本発明の実施の形態3におけるフレキシブルプリント基板の構成を示す断面図であり、図9、図10のVII-VII線に沿う断面図である。FIG. 11 is a cross-sectional view showing a configuration of a flexible printed circuit board according to Embodiment 3 of the present invention, and is a cross-sectional view taken along line VII-VII in FIGS. 9 and 10. 本発明の実施の形態3におけるフレキシブルプリント基板の構成を示す断面図であり、図9、図10のVIII-VIII線に沿う断面図である。FIG. 11 is a cross-sectional view showing a configuration of a flexible printed circuit board according to Embodiment 3 of the present invention, and is a cross-sectional view taken along the line VIII-VIII in FIGS. 9 and 10. 本発明の実施の形態3におけるフレキシブルプリント基板の構成を示す平面図である。It is a top view which shows the structure of the flexible printed circuit board in Embodiment 3 of this invention. 本発明の実施の形態3におけるフレキシブルプリント基板の構成を示す背面図である。It is a rear view which shows the structure of the flexible printed circuit board in Embodiment 3 of this invention. 本発明の実施の形態3におけるフレキシブルプリント基板が接続される相手方のプリント基板の構成を示す平面図である。It is a top view which shows the structure of the other party printed circuit board to which the flexible printed circuit board in Embodiment 3 of this invention is connected. 本発明の実施の形態1におけるフレキシブルプリント基板とプリント基板とを、異方導電性接着フイルムを用いて接続した形態を示す断面図である。It is sectional drawing which shows the form which connected the flexible printed circuit board and printed circuit board in Embodiment 1 of this invention using the anisotropically conductive adhesive film. 本発明の実施の形態1におけるフレキシブルプリント基板に保護層を追加した構成を示す断面図である。It is sectional drawing which shows the structure which added the protective layer to the flexible printed circuit board in Embodiment 1 of this invention. 本発明の実施の形態1におけるフレキシブルプリント基板に保護層を追加した構成を示す断面図であり、電源配線および補助電源回路の長手方向の構成を示す断面図である。It is sectional drawing which shows the structure which added the protective layer to the flexible printed circuit board in Embodiment 1 of this invention, and is sectional drawing which shows the structure of the longitudinal direction of a power supply wiring and an auxiliary power supply circuit.
 以下、本発明の実施の形態について図面を用いて説明する。
 実施の形態1.
 本発明の実施の形態1におけるフレキシブルプリント基板100の構成について図1~図3を用いて説明する。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
The configuration of flexible printed circuit board 100 according to Embodiment 1 of the present invention will be described with reference to FIGS.
 図1に示されるように、本実施の形態のフレキシブルプリント基板100は、ベースフィルム1と、複数の第1導体2、4、6、8と、複数の第2導体3、7、9と、接続導体5とを主に有している。 As shown in FIG. 1, the flexible printed circuit board 100 of the present embodiment includes a base film 1, a plurality of first conductors 2, 4, 6, 8, a plurality of second conductors 3, 7, 9, It mainly has a connection conductor 5.
 ベースフィルム1は、互いに対向する主面(第1面)1aおよび背面(第2面)1bを有しており、絶縁体よりなっている。ベースフィルム1は、互いに異なる仕様の複数の電気回路の形成領域を有している。複数の電気回路形成領域は、たとえば高周波回路部20と、電源回路部30と、制御回路部40とを有している。 The base film 1 has a main surface (first surface) 1a and a back surface (second surface) 1b facing each other, and is made of an insulator. The base film 1 has a plurality of electric circuit forming regions having different specifications. The plurality of electric circuit formation regions include, for example, a high frequency circuit unit 20, a power supply circuit unit 30, and a control circuit unit 40.
 複数の第1導体2、4、6、8の各々は、ベースフィルム1の主面1aに形成されている。複数の第1導体2、4、6、8は、たとえば中心導体2と、接地導体4と、電源回路6と、制御信号回路8とを有している。 Each of the plurality of first conductors 2, 4, 6, 8 is formed on the main surface 1 a of the base film 1. The plurality of first conductors 2, 4, 6, 8 include, for example, a center conductor 2, a ground conductor 4, a power supply circuit 6, and a control signal circuit 8.
 複数の第2導体3、7、9の各々は、ベースフィルム1の背面1bに形成されている。複数の第2導体3、7、9は、たとえば背面接地導体3と、補助電源回路7と、ダミー回路9とを有している。 Each of the plurality of second conductors 3, 7, 9 is formed on the back surface 1 b of the base film 1. The plurality of second conductors 3, 7, 9 have, for example, a back ground conductor 3, an auxiliary power supply circuit 7, and a dummy circuit 9.
 複数の接続導体5の各々は、ベースフィルム1を貫通し、かつ複数の第1導体2、4、6、8の一部と複数の第2導体3、7、9の一部とを電気的に接続している。ベースフィルム1にはスルーホール5aが形成されており、このスルーホール5a内に接続導体5が埋め込まれている。 Each of the plurality of connection conductors 5 penetrates the base film 1, and electrically connects a part of the plurality of first conductors 2, 4, 6, 8 and a part of the plurality of second conductors 3, 7, 9. Connected to. A through hole 5a is formed in the base film 1, and a connection conductor 5 is embedded in the through hole 5a.
 スルーホール5aは、ベースフィルム1だけでなく、第1導体および第2導体の各々も貫通していてもよい。この場合、スルーホール5a内に埋め込まれる接続導体5も、第1導体および第2導体を貫通している。 The through hole 5a may penetrate not only the base film 1 but also each of the first conductor and the second conductor. In this case, the connection conductor 5 embedded in the through hole 5a also passes through the first conductor and the second conductor.
 複数の接続導体5は、高周波回路部20に形成された高周波回路用接続導体5と、電源回路部30に形成された電源回路用接続導体5とを有している。 The plurality of connection conductors 5 include a high-frequency circuit connection conductor 5 formed in the high-frequency circuit unit 20 and a power supply circuit connection conductor 5 formed in the power supply circuit unit 30.
 複数の第2導体3、7、9の各々の膜厚T1は、複数の第1導体2、4、6、8の各々の膜厚T2よりも厚く設定されている。 The film thickness T1 of each of the plurality of second conductors 3, 7, 9 is set to be thicker than the film thickness T2 of each of the plurality of first conductors 2, 4, 6, 8.
 以下、本実施の形態のフレキシブルプリント基板100の構成について、より具体的に説明する。 Hereinafter, the configuration of the flexible printed circuit board 100 of the present embodiment will be described more specifically.
 ベースフィルム1には、たとえば厚さ12.5μm以上50μm以下のポリイミドフイルムなどの可撓性、耐熱性に優れた誘電損失の低い高分子フィルムを用いることができる。 As the base film 1, for example, a polymer film having excellent flexibility and heat resistance, such as a polyimide film having a thickness of 12.5 μm to 50 μm, and a low dielectric loss can be used.
 薄い複数の第1導体2、4、6、8の各々は、たとえば銅の薄膜(銅箔)と、ニッケルの薄膜と、金の薄膜とにより構成されている。銅箔は、ベースフィルム1の主面1a上に形成されており、たとえば6μm以上18μm以下の膜厚を有している。ニッケルの薄膜は、銅箔の表面上に形成されており、たとえば3μm以上5μm以下の膜厚を有している。金の薄膜は、ニッケルの薄膜の表面上に形成されており、たとえば約0.01μmの膜厚を有している。銅箔の表面上のニッケルの薄膜および金の薄膜は、薄い導体層の酸化防止およびはんだ濡れ性向上を目的として形成されている。 Each of the plurality of thin first conductors 2, 4, 6, 8 is composed of, for example, a copper thin film (copper foil), a nickel thin film, and a gold thin film. The copper foil is formed on the main surface 1a of the base film 1, and has a film thickness of, for example, 6 μm or more and 18 μm or less. The nickel thin film is formed on the surface of the copper foil, and has a film thickness of, for example, 3 μm or more and 5 μm or less. The gold thin film is formed on the surface of the nickel thin film, and has a thickness of about 0.01 μm, for example. The nickel thin film and the gold thin film on the surface of the copper foil are formed for the purpose of preventing oxidation of the thin conductor layer and improving solder wettability.
 厚い複数の第2導体3、7、9の各々は、たとえば銅箔と、ニッケルの薄膜と、金の薄膜とにより構成されている。銅箔は、ベースフィルム1の背面1b上に形成されており、たとえば18μm以上70μm以下の膜厚を有している。ニッケルの薄膜は、銅箔の表面上に形成されており、たとえば3μm以上5μm以下の膜厚を有している。金の薄膜は、ニッケルの薄膜の表面上に形成されており、たとえば約0.01μmの膜厚を有している。銅箔の表面上のニッケルの薄膜および金の薄膜は、第1導体2、4、6、8と同様、薄い導体層の酸化防止およびはんだ濡れ性向上を目的として形成されている。 Each of the thick plurality of second conductors 3, 7, 9 is composed of, for example, a copper foil, a nickel thin film, and a gold thin film. The copper foil is formed on the back surface 1b of the base film 1, and has a film thickness of, for example, 18 μm or more and 70 μm or less. The nickel thin film is formed on the surface of the copper foil, and has a film thickness of, for example, 3 μm or more and 5 μm or less. The gold thin film is formed on the surface of the nickel thin film, and has a thickness of about 0.01 μm, for example. Similar to the first conductors 2, 4, 6, and 8, the nickel thin film and the gold thin film on the surface of the copper foil are formed for the purpose of preventing oxidation of the thin conductor layer and improving solder wettability.
 第1導体2、4、6、8および第2導体3、7、9の各々の銅箔とベースフィルム1のポリイミドフイルム基材とは、図示しないエポキシ樹脂系接着剤またはアクリル樹脂系接着剤により接着されている。 The copper foil of each of the first conductors 2, 4, 6, 8 and the second conductors 3, 7, 9 and the polyimide film substrate of the base film 1 are made of an epoxy resin adhesive or an acrylic resin adhesive not shown. It is glued.
 上記銅箔とポリイミド基材とは、高周波特性などの電気特性を重視して、接着剤を用いずに互いに接続されていてもよい。具体的には、銅箔がポリイミドワニスをコーティングされた後に焼成される方法、またはポリイミドフィルム基材にスパッタリングとめっきを用いて金属導体層を形成する方法によって、上記銅箔とポリイミドフィルム基材とが接続されてもよい。 The copper foil and the polyimide base material may be connected to each other without using an adhesive, focusing on electric characteristics such as high-frequency characteristics. Specifically, the copper foil and the polyimide film substrate are formed by a method in which the copper foil is baked after being coated with the polyimide varnish, or a method in which a metal conductor layer is formed on the polyimide film substrate using sputtering and plating. May be connected.
 なお、一般のフレキシブルプリント基板100には上記以外の構成部材、たとえばソルダーレジスト、カバーレイなどの保護膜が設けられることも多い。しかし、これらの保護膜は本発明には関連しない部材なので説明を省略する。 It should be noted that the general flexible printed circuit board 100 is often provided with a protective film such as a component other than the above, for example, a solder resist or a coverlay. However, since these protective films are members not related to the present invention, description thereof is omitted.
 次に、本実施の形態におけるフレキシブルプリント基板100の各構成部材を図1~図3を用いて電気回路面から説明する。 Next, each component of the flexible printed circuit board 100 according to the present embodiment will be described from the electric circuit side with reference to FIGS.
 図1~図3に示されるように、ベースフィルム1は、互いに異なる仕様の異なる複数の電気回路の形成領域として、たとえば高周波回路部20と、電源回路部30と、制御回路部40とを有している。これらの電気回路部20、30、40の各々は、ベースフィルム1の主面1aに形成された第1導体2、4、6、8と、背面1bに形成された第2導体3、7、9とが一体的に機能することで回路機能を発揮する構成となっている。 As shown in FIGS. 1 to 3, the base film 1 has, for example, a high-frequency circuit unit 20, a power circuit unit 30, and a control circuit unit 40 as regions for forming a plurality of electric circuits having different specifications. is doing. Each of these electric circuit portions 20, 30, 40 includes a first conductor 2, 4, 6, 8 formed on the main surface 1a of the base film 1, and a second conductor 3, 7, formed on the back surface 1b. 9 is configured to function as a single unit so that the circuit function is exhibited.
 まず高周波回路部20について説明する。
 図1に示されるように、高周波回路部20において、ベースフィルム1の主面1a上には2種類の導体から成る伝送線路が形成されている。すなわちフレキシブルプリント基板100の主面1a上には、中心導体2と、その中心導体2の両隣に位置する1対の接地導体4とが形成されている。中心導体2および1対の接地導体4の各々は、図2に示されるように直線状の伝送線路である。中心導体2の長手方向と1対の接地導体4の各々の長手方向とが互いに並走するように中心導体2と1対の接地導体4の各々とが並んでいる。
First, the high-frequency circuit unit 20 will be described.
As shown in FIG. 1, in the high-frequency circuit unit 20, transmission lines made of two kinds of conductors are formed on the main surface 1 a of the base film 1. That is, on the main surface 1 a of the flexible printed circuit board 100, the center conductor 2 and a pair of ground conductors 4 located on both sides of the center conductor 2 are formed. Each of the center conductor 2 and the pair of ground conductors 4 is a linear transmission line as shown in FIG. The central conductor 2 and each of the pair of ground conductors 4 are arranged so that the longitudinal direction of the central conductor 2 and the longitudinal direction of each of the pair of ground conductors 4 are parallel to each other.
 高周波回路部20において、ベースフィルム1の背面1b上には背面接地導体3が形成されている。1対の接地導体4の各々は、スルーホール5a内を埋め込む高周波回路用接続導体5によって1つの背面接地導体3に電気的に接続されている。 In the high-frequency circuit unit 20, the back ground conductor 3 is formed on the back surface 1 b of the base film 1. Each of the pair of ground conductors 4 is electrically connected to one back ground conductor 3 by a high-frequency circuit connection conductor 5 that fills the through hole 5a.
 以上述べた高周波回路部20において、最低限の伝送線路の構成は中心導体2と接地導体4との組み合わせであり、この組み合わせによりコプレーナ構造が得られる。また他の最低限の伝送線路の構成は中心導体2と背面接地導体3との組み合わせであり、この組み合わせによりマイクロストリップ構造が得られる。 In the high-frequency circuit unit 20 described above, the minimum transmission line configuration is a combination of the center conductor 2 and the ground conductor 4, and a coplanar structure is obtained by this combination. Another minimum transmission line configuration is a combination of the center conductor 2 and the back ground conductor 3, and a microstrip structure can be obtained by this combination.
 ただし中心導体2、接地導体4および背面接地導体3の組合せとすることで、コプレーナ構造とマイクロストリップ構造とを併用する構造が得られる。この併用構造により、高周波の伝送損失をより低減できるという効果が得られる。 However, by using a combination of the center conductor 2, the ground conductor 4, and the back ground conductor 3, a structure using both a coplanar structure and a microstrip structure can be obtained. With this combined structure, an effect of further reducing high-frequency transmission loss can be obtained.
 中心導体2の導体寸法、形状および配置は、高周波信号を最も効率よく伝送できるように設計される。具体的には、中心導体2の導体寸法、形状および配置は、信号を伝送する中心導体2の導電率と、中心導体2(および接地導体4)と背面接地導体3とを隔てるベースフィルム1の厚さと、ベースフィルム1の誘電率とをもとに電磁界シミュレーションを行なうことによって求められればよい。 The conductor dimensions, shape, and arrangement of the center conductor 2 are designed so that high-frequency signals can be transmitted most efficiently. Specifically, the conductor dimensions, shape, and arrangement of the center conductor 2 are such that the conductivity of the center conductor 2 that transmits signals and the base film 1 that separates the center conductor 2 (and the ground conductor 4) and the back ground conductor 3 from each other. What is necessary is just to obtain | require by performing electromagnetic field simulation based on the thickness and the dielectric constant of the base film 1.
 また中心導体2の導体厚さは、製造上および使用上において問題無い程度まで薄くされてもよい。すなわち中心導体2の導体厚さは、中心導体2において回路の抵抗増大を招く現象として知られる表皮効果の影響を受けない程度までであれば可能な限り薄くされてもよい。結果として、中心導体2のパターニング時のエッチングにおいて中心導体2の断面形状が台形になるという、サイドエッチング現象が最小限になる。これにより、上記の電磁界シミュレーションで求めた導体の形状を高精度に再現した基板が製造可能である。具体的には導体厚さは6μm以上18μm以下の範囲であることが望ましい。 Also, the conductor thickness of the center conductor 2 may be reduced to such an extent that there is no problem in manufacturing and use. That is, the conductor thickness of the center conductor 2 may be made as thin as possible as long as it is not affected by the skin effect known as a phenomenon that causes an increase in circuit resistance in the center conductor 2. As a result, the side etching phenomenon that the cross-sectional shape of the central conductor 2 becomes trapezoid in the etching during patterning of the central conductor 2 is minimized. Thereby, it is possible to manufacture a substrate in which the shape of the conductor obtained by the electromagnetic field simulation is reproduced with high accuracy. Specifically, the conductor thickness is desirably in the range of 6 μm to 18 μm.
 一方、背面接地導体3に関しては導体厚さの薄膜化は不要である。その理由は、背面接地導体3に求められる特性が接地導体としての機能だけであることによる。すなわち背面接地導体3は、ベースフィルム1の背面1b側と接している部分だけが接地導体として機能すればよいのであって、その導体厚さは薄くても厚くても同じように接地導体として作用する。具体的には背面接地導体3の導体厚さは、中心導体2より厚く、かつ70μm以下程度であれば問題は無い。 On the other hand, it is not necessary to reduce the thickness of the conductor for the back ground conductor 3. This is because the characteristic required for the back ground conductor 3 is only the function as the ground conductor. That is, the back ground conductor 3 only needs to function as a ground conductor only at the portion in contact with the back surface 1b side of the base film 1, and the conductor acts as a ground conductor even if the conductor thickness is thin or thick. To do. Specifically, there is no problem if the conductor thickness of the back ground conductor 3 is thicker than the center conductor 2 and about 70 μm or less.
 図2および図3に示されるように、高周波回路部20において、高周波回路用接続導体5はフレキシブルプリント基板100の長さ方向(接地導体4の延在方向)に沿い、接地導体4の中心線付近に点列状に配置されている。高周波回路用接続導体5は電磁気的には接地導体(シールド壁)として機能している。隣り合う2つの高周波回路用接続導体5同士の最短距離S1は、高周波回路部20を伝送する電磁波の波長をλとすればS1=λ/4の関係を満たすことが好ましい。上記最短距離S1は、可能であればS1≦λ/8の関係を満たすことがより好ましい。高周波回路用接続導体5の直径は50μm以上300μm以下であることが望ましい。 As shown in FIGS. 2 and 3, in the high-frequency circuit unit 20, the high-frequency circuit connection conductor 5 extends along the length direction of the flexible printed circuit board 100 (the extending direction of the ground conductor 4), and the center line of the ground conductor 4. It is arranged in the vicinity of a point sequence. The high-frequency circuit connection conductor 5 electromagnetically functions as a ground conductor (shield wall). The shortest distance S1 between two adjacent high-frequency circuit connection conductors 5 preferably satisfies the relationship S1 = λ / 4, where λ is the wavelength of the electromagnetic wave transmitted through the high-frequency circuit unit 20. It is more preferable that the shortest distance S1 satisfies the relationship of S1 ≦ λ / 8 if possible. The diameter of the high-frequency circuit connection conductor 5 is preferably 50 μm or more and 300 μm or less.
 以上より高周波回路部20の設計に際し使用周波数に応じて最適化された伝送回路を設計することにより、フレキシブルプリント基板100においても高品位な高周波信号の伝送が可能となる。 As described above, by designing a transmission circuit that is optimized according to the frequency used when designing the high-frequency circuit section 20, high-quality high-frequency signals can be transmitted even on the flexible printed circuit board 100.
 次に電源回路部30について説明する。
 図1~図3に示されるように、電源回路部30において、ベースフィルム1の主面1a上には電源回路6が設けられている。電源回路部30において、ベースフィルム1の背面1b上には補助電源回路7が設けられている。補助電源回路7は、ベースフィルム1を介在して電源回路6と対向する位置に配置されている。補助電源回路7は、大電流を送るために電源回路6に付随して設けられるバイパス回路を指す。すなわち、補助電源回路7の金属導体の厚さは、少なくとも電源回路6以上に厚く設計されており、電源回路6と補助電源回路7の合計の電流容量でもって、大電流の送電が可能となる。
Next, the power supply circuit unit 30 will be described.
As shown in FIGS. 1 to 3, in the power supply circuit unit 30, the power supply circuit 6 is provided on the main surface 1 a of the base film 1. In the power circuit 30, an auxiliary power circuit 7 is provided on the back surface 1 b of the base film 1. The auxiliary power circuit 7 is disposed at a position facing the power circuit 6 with the base film 1 interposed. The auxiliary power supply circuit 7 refers to a bypass circuit provided in association with the power supply circuit 6 in order to send a large current. That is, the thickness of the metal conductor of the auxiliary power circuit 7 is designed to be at least thicker than the power circuit 6, and a large current can be transmitted with the total current capacity of the power circuit 6 and the auxiliary power circuit 7. .
 複数の電源回路6の各々の長手方向が互いに並走するように複数の電源回路6の各々が並んでいる。中心導体2の長手方向と複数の電源回路6の各々の長手方向とが互いに並走するように中心導体2と複数の電源回路6の各々とが並んでいる。また複数の補助電源回路7の各々の長手方向が互いに並走するように複数の補助電源回路7の各々が並んでいる。 Each of the plurality of power supply circuits 6 is arranged so that the longitudinal directions of the plurality of power supply circuits 6 run parallel to each other. The center conductor 2 and each of the plurality of power supply circuits 6 are arranged so that the longitudinal direction of the center conductor 2 and each of the plurality of power supply circuits 6 run in parallel with each other. Each of the plurality of auxiliary power supply circuits 7 is arranged so that the longitudinal directions of the plurality of auxiliary power supply circuits 7 run in parallel with each other.
 電源回路6と補助電源回路7とは、互いに電源回路用接続導体5によって電気的に接続されている。後述する電流容量確保のため電源回路用接続導体5を複数個設けることができる。電源回路部30には、負荷として接続される回路の消費電力が大きな場合に備えて大電流を通電可能な構造を有していることが求められる。 The power supply circuit 6 and the auxiliary power supply circuit 7 are electrically connected to each other by a power supply circuit connection conductor 5. A plurality of power supply circuit connection conductors 5 can be provided to secure a current capacity to be described later. The power supply circuit unit 30 is required to have a structure capable of supplying a large current in preparation for a case where power consumption of a circuit connected as a load is large.
 回路の電流容量を増すには導体の断面積を大きくする必要がある。しかし、電源回路6の導体厚さは、主面1aに形成される第1導体の厚さ、すなわち中心導体2が最も効率よく高周波を伝送できる導体厚さと同じ厚さに設計されている。このため、電流容量を大きくするために電源回路6の導体厚さを増すことはできない。また電源回路6の幅を広くするという方法は、フレキシブルプリント基板100に求められる小型化、省スペース化の観点から採用できない。 To increase the current capacity of the circuit, it is necessary to increase the cross-sectional area of the conductor. However, the conductor thickness of the power supply circuit 6 is designed to be the same as the thickness of the first conductor formed on the main surface 1a, that is, the thickness of the conductor at which the center conductor 2 can transmit high frequency most efficiently. For this reason, the conductor thickness of the power supply circuit 6 cannot be increased in order to increase the current capacity. Further, the method of widening the power supply circuit 6 cannot be adopted from the viewpoint of miniaturization and space saving required for the flexible printed circuit board 100.
 そこで、実施の形態1においては、主面1aに形成された電源回路6に対向するように背面1bに補助電源回路7が設けられ、電源回路6と補助電源回路7とが電源回路用接続導体5により電気的に接続されている。このように補助電源回路7がベースフィルム1を挟んで電源回路6と対向する位置に配置されているため、補助電源回路7の導体幅は電源回路6の導体幅と等しくなる。このため補助電源回路7が設けられても電源回路部30の幅が広くなることはない。 Therefore, in the first embodiment, the auxiliary power circuit 7 is provided on the back surface 1b so as to face the power circuit 6 formed on the main surface 1a, and the power circuit 6 and the auxiliary power circuit 7 are connected to the power circuit connecting conductor. 5 is electrically connected. Thus, since the auxiliary power circuit 7 is arranged at a position facing the power circuit 6 with the base film 1 interposed therebetween, the conductor width of the auxiliary power circuit 7 is equal to the conductor width of the power circuit 6. For this reason, even if the auxiliary power supply circuit 7 is provided, the width of the power supply circuit section 30 does not increase.
 また補助電源回路7は、ベースフィルム1の背面1bに形成されているため、主面1aに形成された中心導体2と同じ厚さにしなければならないという、製造プロセス的な制約を受けない。このため補助電源回路7は、製造プロセス的な制約を受けずに背面接地導体3と同じ厚い導体厚さで形成することができる。 Further, since the auxiliary power circuit 7 is formed on the back surface 1b of the base film 1, there is no restriction on the manufacturing process that the same thickness as that of the central conductor 2 formed on the main surface 1a is required. Therefore, the auxiliary power supply circuit 7 can be formed with the same thick conductor thickness as that of the back ground conductor 3 without being restricted by the manufacturing process.
 この構造により大電流の通電に必要な導体の断面積は電源回路6と補助電源回路7とを合わせた断面積で確保できることになる。これにより、前述した導体の断面積が不足するという課題を解消できるため、設計上の自由度を大きく向上させることができる。 With this structure, the cross-sectional area of the conductor necessary for energizing a large current can be secured by the combined cross-sectional area of the power supply circuit 6 and the auxiliary power supply circuit 7. Thereby, since the subject that the cross-sectional area of the conductor mentioned above is insufficient can be solved, the degree of freedom in design can be greatly improved.
 電源回路部30における電源回路用接続導体5の数は、補助電源回路7の断面積に基づいて設定されればよい。すなわち電源回路用接続導体5を輪切りした時の断面積と電源回路用接続導体5の数の積算値が、補助電源回路7の断面積に等しいかそれより大きくなるように設計されればよい。 The number of power supply circuit connection conductors 5 in the power supply circuit unit 30 may be set based on the cross-sectional area of the auxiliary power supply circuit 7. That is, the cross-sectional area when the power supply circuit connection conductor 5 is cut and the integrated value of the number of the power supply circuit connection conductors 5 may be designed to be equal to or larger than the cross-sectional area of the auxiliary power supply circuit 7.
 上記のような構造により、本実施の形態におけるフレキシブルプリント基板100の電源回路部30において大電流の伝送が可能となる。 With the structure as described above, a large current can be transmitted in the power supply circuit unit 30 of the flexible printed circuit board 100 in the present embodiment.
 次に制御回路部40について説明する。
 図1~図3に示されるように、制御回路部40において、ベースフィルム1の主面1a上には制御信号回路8が設けられている。制御回路部40において、ベースフィルム1の背面1b上にはダミー回路9が設けられている。
Next, the control circuit unit 40 will be described.
As shown in FIGS. 1 to 3, the control signal circuit 8 is provided on the main surface 1 a of the base film 1 in the control circuit unit 40. In the control circuit unit 40, a dummy circuit 9 is provided on the back surface 1 b of the base film 1.
 複数の制御信号回路8の各々の長手方向が互いに並走するように複数の制御信号回路8の各々が並んでいる。また複数の制御信号回路8の各々の長手方向と複数の電源回路6の各々の長手方向とが互いに並走するように複数の制御信号回路8の各々と複数の電源回路6の各々とが並んでいる。 Each of the plurality of control signal circuits 8 is arranged so that the longitudinal directions of the plurality of control signal circuits 8 run parallel to each other. Further, each of the plurality of control signal circuits 8 and each of the plurality of power supply circuits 6 are arranged so that the longitudinal direction of each of the plurality of control signal circuits 8 and each longitudinal direction of the plurality of power supply circuits 6 run in parallel with each other. It is out.
 制御信号回路8はデジタル回路である。このため制御信号回路8は、ノイズの影響を受けやすいアナログ回路の高周波回路部20または発熱の問題を検討せねばならない電源回路部30と異なり、電気回路的には特段の配慮をしなくても作動させることができる。よって制御信号回路8を製造面で可能なかぎり高密度に配置することができる。 The control signal circuit 8 is a digital circuit. For this reason, the control signal circuit 8 is different from the high-frequency circuit unit 20 of an analog circuit that is easily affected by noise or the power supply circuit unit 30 that has to examine the problem of heat generation, even if no special consideration is required in terms of electrical circuit. Can be operated. Therefore, the control signal circuits 8 can be arranged as densely as possible in terms of manufacturing.
 このような高密度な配線はラインアンドスペースで表現される。ラインアンドスペースは、配線の導体幅をラインと呼び、隣り合う配線同士の間隔(または配線と導体パッドとの距離)をスペースと呼ぶものである。 Such high-density wiring is expressed in line and space. In the line and space, the conductor width of the wiring is called a line, and the interval between adjacent wirings (or the distance between the wiring and the conductor pad) is called a space.
 本実施の形態では制御信号回路8の導体厚さは、中心導体2の導体厚さと等しく形成される。そのため制御信号回路8の導体厚さは、製造上および使用上において限界近くまで薄くした中心導体2の設計指針である6μm以上18μm以下の範囲で設計されている。これにより制御信号回路8においても、サイドエッチング現象は最小限になる。 In this embodiment, the conductor thickness of the control signal circuit 8 is formed to be equal to the conductor thickness of the center conductor 2. Therefore, the conductor thickness of the control signal circuit 8 is designed in the range of 6 μm or more and 18 μm or less, which is a design guideline for the center conductor 2 thinned to the limit in manufacturing and use. Thereby, also in the control signal circuit 8, the side etching phenomenon is minimized.
 したがって、ラインアンドスペース的には十分に高密度な回路配線の形成が可能である。具体的には実施の形態1における制御信号回路8のラインアンドスペースは50μm(ライン)/50μm(スペース)~150μm(ライン)/150μm(スペース)である。 Therefore, it is possible to form a sufficiently high density circuit wiring in line and space. Specifically, the line and space of the control signal circuit 8 in the first embodiment is 50 μm (line) / 50 μm (space) to 150 μm (line) / 150 μm (space).
 ダミー回路9は、制御回路部40以外の背面1bの回路、すなわち背面接地導体3および補助電源回路7と等しい導体厚さを有する回路である。ダミー回路9により、制御回路部40における厚さ(ベースフィルム1の厚さと制御信号回路8の厚さとダミー回路9の厚さとの総和)を、高周波回路部20の厚さ(ベースフィルム1の厚さと中心導体2の厚さと背面接地導体3の厚さとの総和)および電源回路部30における厚さ(ベースフィルム1の厚さと電源回路6の厚さと補助電源回路7の厚さとの総和)と等しくすることができる。ダミー回路9は、フレキシブルプリント基板100全体の剛性、厚さ、取扱い上から検討することによって設ける必要がないと判断されれば省略することもできる。フレキシブルプリント基板100におけるダミー回路9は、フローティングであるが、制御信号回路8がノイズに影響されやすい場合などは、必要に応じて接地導体と電気的に接続することができる。 The dummy circuit 9 is a circuit having a conductor thickness equal to that of the circuit on the back surface 1 b other than the control circuit unit 40, that is, the back surface ground conductor 3 and the auxiliary power supply circuit 7. The dummy circuit 9 allows the thickness in the control circuit unit 40 (the total of the thickness of the base film 1, the thickness of the control signal circuit 8 and the thickness of the dummy circuit 9) to be the thickness of the high-frequency circuit unit 20 (the thickness of the base film 1). And the thickness of the central conductor 2 and the thickness of the back ground conductor 3) and the thickness in the power supply circuit section 30 (the sum of the thickness of the base film 1, the power supply circuit 6, and the auxiliary power supply circuit 7). can do. The dummy circuit 9 may be omitted if it is determined that it is not necessary to provide the dummy circuit 9 by considering the rigidity, thickness, and handling of the flexible printed circuit board 100 as a whole. Although the dummy circuit 9 in the flexible printed circuit board 100 is floating, when the control signal circuit 8 is easily affected by noise, it can be electrically connected to the ground conductor as necessary.
 次に本実施の形態におけるフレキシブルプリント基板100を用いた場合の接続形態について説明する。 Next, a connection form when using the flexible printed circuit board 100 in the present embodiment will be described.
 たとえばプリント基板間をフレキシブルプリント基板を用いて電気的に接続する形態(プリント基板-フレキシブルプリント基板-プリント基板)には次に述べるような接続形態がある。 For example, a form of electrically connecting printed boards using a flexible printed board (printed board-flexible printed board-printed board) includes the following connected forms.
 まず、コネクタによる接続について述べる。ワイヤーハーネス用コネクタとは異なり、フレキシブルプリント基板用コネクタでは、樹脂製の扁平なコネクタの内部に金属端子が設けられている。このコネクタの内部にフレキシブルプリント基板が挿入された後に、樹脂製のカバーが閉じられる。これにより、フレキシブルプリント基板の端子がコネクタ内部の端子に機械的に押し付けられることで両者が電気的に接続される。 First, the connection with the connector will be described. Unlike a connector for a wire harness, a flexible printed circuit board connector has a metal terminal provided inside a flat resin connector. After the flexible printed board is inserted into the connector, the resin cover is closed. As a result, the terminals of the flexible printed circuit board are mechanically pressed against the terminals inside the connector, whereby the two are electrically connected.
 このような接続方法の場合、フレキシブルプリント基板の面内で厚さが異なると、コネクタのカバーを閉じる際にフレキシブルプリント基板にかかる荷重が不均一になる。これにより、フレキシブルプリント基板の端子とコネクタ内部の端子との間で導通不良を生じる懸念がある。 In the case of such a connection method, if the thickness is different in the plane of the flexible printed circuit board, the load applied to the flexible printed circuit board when the connector cover is closed becomes uneven. Thereby, there exists a possibility of producing a conduction defect between the terminal of a flexible printed circuit board, and the terminal inside a connector.
 これに対して本実施の形態におけるフレキシブルプリント基板100では、上記のとおり、制御回路部40における厚さを、高周波回路部20の厚さおよび電源回路部30における厚さと等しくすることができる。このため上記コネクタによる接続では、フレキシブルプリント基板100の端子とコネクタ内部の端子との間で荷重が不均一になることが抑制される。よって、フレキシブルプリント基板100の端子とコネクタ内部の端子との間で導通不良が生じにくくなり、高信頼性のコネクタ接続が可能となる。 On the other hand, in the flexible printed circuit board 100 according to the present embodiment, as described above, the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, in the connection by the said connector, it is suppressed that a load becomes nonuniform between the terminal of the flexible printed circuit board 100, and the terminal inside a connector. As a result, poor conduction is unlikely to occur between the terminals of the flexible printed circuit board 100 and the terminals inside the connector, and a highly reliable connector connection is possible.
 次に、異方導電性接着フィルム(以下、ACFとも呼ぶ)による接続について述べる。
 図12に示されるように、本実施の形態におけるフレキシブルプリント基板100とプリント基板200とは、たとえばACFを用いて接続される。ACFは、バインダーとなる樹脂11中に、直径数μm~数十μmの導電粒子12を含んでいる。導電粒子12には、ニッケル粒子または金属のめっきが施された樹脂粒子がよく用いられる。
Next, connection by an anisotropic conductive adhesive film (hereinafter also referred to as ACF) will be described.
As shown in FIG. 12, flexible printed circuit board 100 and printed circuit board 200 in the present embodiment are connected using, for example, ACF. The ACF includes conductive particles 12 having a diameter of several μm to several tens of μm in a resin 11 serving as a binder. For the conductive particles 12, nickel particles or resin particles plated with metal are often used.
 ACFによる接続では、プリント基板200における基板201上のパッド電極202、204、206、208とフレキシブルプリント基板100の端子2、4、6、8との間にACFの導電粒子12が挟み込まれた状態で適正な荷重が印加される。これによってプリント基板200のパッド電極202、204、206、208とフレキシブルプリント基板100の端子2、4、6、8との間に電気的導通が得られる。 In the connection by ACF, the conductive particles 12 of ACF are sandwiched between the pad electrodes 202, 204, 206, 208 on the printed circuit board 200 and the terminals 2, 4, 6, 8 of the flexible printed circuit board 100. A proper load is applied. As a result, electrical conduction is obtained between the pad electrodes 202, 204, 206, 208 of the printed circuit board 200 and the terminals 2, 4, 6, 8 of the flexible printed circuit board 100.
 このような接続方法の場合、仮にフレキシブルプリント基板100の面内で厚さが異なると、導電粒子12を捕捉するための荷重がフレキシブルプリント基板100の面内で不均一に加わる。これにより、ACFの導電粒子12が十分に捕捉されない端子2、4、6、8が生じることで導通不良が起こる懸念がある。 In the case of such a connection method, if the thickness is different in the plane of the flexible printed board 100, a load for capturing the conductive particles 12 is applied unevenly in the plane of the flexible printed board 100. As a result, there is a concern that poor conduction may occur due to the terminals 2, 4, 6, and 8 in which the conductive particles 12 of the ACF are not sufficiently captured.
 これに対して本実施の形態におけるフレキシブルプリント基板100では、上記のとおり、制御回路部40における厚さを、高周波回路部20の厚さおよび電源回路部30における厚さと等しくすることができる。このため、ACFの導電粒子12を捕捉するために必要な荷重がフレキシブルプリント基板100の面内で均等に加わる。これにより、フレキシブルプリント基板100のすべての端子2、4、6、8で導電粒子12を均等に挟みこむことが可能になるため、信頼性の高い導通を得ることができる。 On the other hand, in the flexible printed circuit board 100 according to the present embodiment, as described above, the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, a load necessary for capturing the conductive particles 12 of ACF is evenly applied in the plane of the flexible printed circuit board 100. Thereby, since it becomes possible to pinch | interpose the electrically-conductive particle 12 by all the terminals 2, 4, 6, and 8 of the flexible printed circuit board 100, highly reliable conduction | electrical_connection can be obtained.
 次に、はんだを用いた接続について述べる。フレキシブルプリント基板の面内で導体表面に段差が生じるとはんだ付けの際に、溶融したはんだに接触する導体と、接触しない導体とが出てくる可能性があるため、導通不良が生じる懸念がある。 Next, connection using solder will be described. If there is a step on the surface of the conductor in the surface of the flexible printed circuit board, there is a possibility that a conductor that contacts the molten solder and a conductor that does not contact may come out during soldering. .
 これに対して本実施の形態におけるフレキシブルプリント基板100では、上記のとおり、制御回路部40における厚さを、高周波回路部20の厚さおよび電源回路部30における厚さと等しくすることができる。このため、はんだにおいても問題なく信頼性の高い導通を得ることができる。 On the other hand, in the flexible printed circuit board 100 according to the present embodiment, as described above, the thickness of the control circuit unit 40 can be made equal to the thickness of the high-frequency circuit unit 20 and the thickness of the power supply circuit unit 30. For this reason, highly reliable conduction can be obtained without problems even in solder.
 次に、本実施の形態の作用効果について、各回路部の課題を説明したうえで、それとの対比で説明する。 Next, the operational effects of the present embodiment will be described in comparison with the problems of each circuit section.
 まず高周波回路特有の課題について説明する。高周波信号を伝送する場合、高周波を伝送する回路の特性インピーダンスと、伝送される先にある負荷または回路のインピーダンスとが異なると、高周波信号がうまく伝わらず伝送効率が低下する。このような効率の低下は反射損失と呼ばれ、低い周波数の信号では無視できることが多いが、周波数を高くすることによって顕在化する。反射損失を低下させて効率よく高周波信号を伝送するためには、高周波回路の特性インピーダンスを、伝送される先にある負荷または回路のインピーダンスと整合させる必要がある。 First, problems specific to high-frequency circuits will be described. When transmitting a high-frequency signal, if the characteristic impedance of the circuit that transmits the high frequency is different from the impedance of the load or circuit that is the transmission destination, the high-frequency signal is not transmitted well, and the transmission efficiency decreases. Such a decrease in efficiency is called reflection loss and is often negligible for low-frequency signals, but it becomes apparent when the frequency is increased. In order to efficiently transmit a high-frequency signal with reduced reflection loss, it is necessary to match the characteristic impedance of the high-frequency circuit with the impedance of the load or circuit that is transmitted.
 フレキシブルプリント基板の特性インピーダンスは、基板材料の厚さと、基板材料の誘電率と、金属導体の厚さと、金属導体の幅とで決定される。このため、これらを適正に設計し、高精度に基板を製造することで特性インピーダンスの整合が可能となる。 The characteristic impedance of the flexible printed circuit board is determined by the thickness of the substrate material, the dielectric constant of the substrate material, the thickness of the metal conductor, and the width of the metal conductor. For this reason, it is possible to match the characteristic impedance by properly designing them and manufacturing the substrate with high accuracy.
 しかしながら、一般的なプリント基板またはフレキシブルプリント基板において導体の回路形成に用いられているエッチング法(サブトラクティブ法)の場合、エッチング工程で薬液が基板の面内方向に進行することによって生じるサイドエッチング現象により、導体の断面形状は台形になる。そのため、設計と実際の出来栄えに差異が生じ、特性インピーダンスの違いとなって回路の特性に影響を与える。このようなサイドエッチング現象による設計値との差異をできる限り小さくするためには、導体厚さを薄くし、導体断面の台形の上底と下底の差を小さくする方法が効果的である。 However, in the case of the etching method (subtractive method) used for circuit formation of a conductor in a general printed circuit board or a flexible printed circuit board, a side etching phenomenon caused by a chemical solution traveling in the in-plane direction of the substrate in the etching process Thus, the cross-sectional shape of the conductor becomes a trapezoid. For this reason, a difference occurs between the design and the actual performance, resulting in a difference in characteristic impedance, which affects the circuit characteristics. In order to reduce the difference from the design value due to such a side etching phenomenon as much as possible, it is effective to reduce the thickness of the conductor and reduce the difference between the trapezoidal upper and lower bases of the conductor cross section.
 以上より、効率のよい高周波回路を形成するためには、信号線の導体厚さを薄くすることが求められる。 From the above, in order to form an efficient high-frequency circuit, it is required to reduce the conductor thickness of the signal line.
 次に電源回路特有の課題について説明する。電源回路においては、多様な回路負荷に対応するために、余裕をもった電流容量を確保することが求められる。この要求を満たすためには金属導体の断面積を大きくすることが必要である。金属導体の断面積を大きくするためには、たとえば金属導体の厚さを厚くするか、金属導体の幅を広くする必要がある。 Next, problems specific to the power supply circuit will be described. In a power supply circuit, it is required to secure a sufficient current capacity in order to cope with various circuit loads. In order to satisfy this requirement, it is necessary to increase the cross-sectional area of the metal conductor. In order to increase the cross-sectional area of the metal conductor, for example, it is necessary to increase the thickness of the metal conductor or increase the width of the metal conductor.
 次に制御回路特有の課題について説明する。制御回路においては、近年デジタル信号の伝送が基本であり、取扱われるパルス信号が必要とする電流容量は非常に小さい。このため、金属導体の断面積に対して特段の配慮は不要である。 Next, problems specific to the control circuit will be described. In the control circuit, digital signal transmission is fundamental in recent years, and the current capacity required by the handled pulse signal is very small. For this reason, special consideration is not necessary for the cross-sectional area of the metal conductor.
 しかし、多機能化した機器を小型化するためには狭小な空間に多くの制御信号を配置する必要があるため、金属導体を高密度に配することが必要である。金属導体を高密度に配するためには、前述のサイドエッチング現象を最小限に抑え、後述するラインアンドスペースを最大限に狭めることが効果的である。 However, in order to reduce the size of a multifunctional device, it is necessary to arrange many control signals in a narrow space, so it is necessary to arrange metal conductors at high density. In order to arrange the metal conductors at a high density, it is effective to minimize the above-mentioned side etching phenomenon and to narrow the line and space described later to the maximum.
 次に上記の高周波回路、電源回路および制御回路を混載した時の課題について説明する。上記に述べたように、効率よく高周波信号を伝送するためには、金属導体の厚さを薄くすることが求められる。しかし、金属導体の厚さを薄くすると断面積が小さくなり、同じ金属導体で大電流を流すことはできない。金属導体の幅を広くすることで断面積を大きくして電流容量を確保する方法もある。しかし、この方法では多数の配線を必要とする制御回路を設ける空間がなくなるばかりでなく、小型機器の内部での狭小な空間にはこの方法を適用することができない。 Next, the problem when the above high frequency circuit, power supply circuit and control circuit are mixedly mounted will be described. As described above, in order to efficiently transmit a high-frequency signal, it is required to reduce the thickness of the metal conductor. However, if the thickness of the metal conductor is reduced, the cross-sectional area is reduced, and a large current cannot flow through the same metal conductor. There is also a method of ensuring current capacity by increasing the cross-sectional area by widening the width of the metal conductor. However, this method not only eliminates a space for providing a control circuit that requires a large number of wirings, but also cannot apply this method to a narrow space inside a small device.
 以上のように、高周波を効率よく伝送する高周波回路と、大電流を送る電源回路と、高密度配線を必要とする制御回路とは、それぞれの回路に求められる金属導体の特徴が相反する。このため、それぞれの回路をコンパクトに一体化することは困難であった。 As described above, the characteristics of the metal conductor required for each circuit of the high-frequency circuit that efficiently transmits high-frequency, the power supply circuit that sends a large current, and the control circuit that requires high-density wiring are contradictory. For this reason, it was difficult to integrate each circuit compactly.
 これに対して本実施の形態においては、図1に示されるように、複数の第2導体3、7、9の各々の膜厚は複数の第1導体2、4、6、8の各々の膜厚よりも厚い。このため薄い膜厚が必要な電気回路は第1導体で形成し、かつ厚い膜厚が必要な電気回路は第2導体で形成することができる。 On the other hand, in the present embodiment, as shown in FIG. 1, the thickness of each of the plurality of second conductors 3, 7, 9 is the same as that of each of the plurality of first conductors 2, 4, 6, 8. Thicker than film thickness. Therefore, an electric circuit that requires a thin film thickness can be formed with the first conductor, and an electric circuit that requires a thick film thickness can be formed with the second conductor.
 具体的には高周波回路部20において中心導体2の導体厚さは、製造上および使用上において問題無い程度まで薄くすることができる。これにより、中心導体2のパターニング時のエッチングにおいて中心導体2の断面形状が台形になるという、サイドエッチング現象が最小限になる。これにより、上記の電磁界シミュレーションで求めた導体の形状を高精度に再現した基板を製造することができる。 Specifically, in the high-frequency circuit section 20, the thickness of the central conductor 2 can be reduced to a level that does not cause a problem in manufacturing and use. Thereby, the side etching phenomenon that the cross-sectional shape of the center conductor 2 becomes trapezoid in the etching at the time of patterning of the center conductor 2 is minimized. Thereby, the board | substrate which reproduced the shape of the conductor calculated | required by said electromagnetic field simulation with high precision can be manufactured.
 また電源回路部30において補助電源回路7は背面1bに形成されているため、主面1aに形成された中心導体2と同じ厚さにしなければならないという、製造プロセス的な制約を受けない。このため補助電源回路7は、製造プロセス的な制約を受けずに背面接地導体3と同じ厚い導体厚さで形成することができる。これにより大電流の通電に必要な導体の断面積を補助電源回路7の断面積で稼ぐことができる。これにより、前述した導体の断面積が不足するという課題を解消できるため、設計上の自由度を大きく向上させることができる。 In addition, since the auxiliary power circuit 7 is formed on the back surface 1b in the power circuit section 30, there is no manufacturing process restriction that the thickness must be the same as that of the center conductor 2 formed on the main surface 1a. Therefore, the auxiliary power supply circuit 7 can be formed with the same thick conductor thickness as that of the back ground conductor 3 without being restricted by the manufacturing process. As a result, the cross-sectional area of the conductor necessary for energizing a large current can be obtained by the cross-sectional area of the auxiliary power supply circuit 7. Thereby, since the subject that the cross-sectional area of the conductor mentioned above is insufficient can be solved, the degree of freedom in design can be greatly improved.
 また制御回路部40において制御信号回路8の導体厚さは、中心導体2と同様、製造上および使用上において問題無い程度まで薄くすることができる。これにより、制御信号回路8のパターニング時のエッチングにおいて制御信号回路8の断面形状が台形になるという、サイドエッチング現象が最小限になる。これにより、制御信号回路8を高密度に配することが可能となる。 Also, in the control circuit section 40, the conductor thickness of the control signal circuit 8 can be reduced to the extent that there is no problem in manufacturing and use, like the central conductor 2. As a result, the side etching phenomenon that the cross-sectional shape of the control signal circuit 8 becomes trapezoid in the etching during patterning of the control signal circuit 8 is minimized. As a result, the control signal circuits 8 can be arranged with high density.
 以上により、複数の電気回路部20、30、40の互いに異なる仕様を満たしながら、一枚のフレキシブルプリント基板100に異なる仕様を必要とする複数の電気回路部20、30、40を形成することができる。これにより異なる仕様を必要とする複数の電気回路を別個に製作して貼り合わせる工程が必要なくなる。よって、高密度で高精度かつ製造コストを低く抑えたフレキシブルプリント基板を実現することができる。 As described above, a plurality of electrical circuit units 20, 30, 40 that require different specifications can be formed on one flexible printed circuit board 100 while satisfying different specifications of the plurality of electrical circuit units 20, 30, 40. it can. This eliminates the need for separately manufacturing and bonding a plurality of electrical circuits that require different specifications. Therefore, it is possible to realize a flexible printed board with high density, high accuracy, and low manufacturing cost.
 また図13および図14に示されるように、フレキシブルプリント基板100の主面1aに保護層13aが、背面1bに保護層13bが設けられてもよい。保護層13a、13bの各々には、ポリイミドなどの可撓性フイルム、またはソルダーレジストなどの感光性樹脂を用いることができる。保護層13a、13bの各々は、フレキシブルプリント基板100の主面1aおよび背面1bの各々に図示しない接着剤によって接着固定され、導体表面を腐食および酸化から保護する。これにより耐環境性能を高めることができる。 Further, as shown in FIGS. 13 and 14, a protective layer 13a may be provided on the main surface 1a of the flexible printed circuit board 100, and a protective layer 13b may be provided on the back surface 1b. For each of the protective layers 13a and 13b, a flexible film such as polyimide or a photosensitive resin such as a solder resist can be used. Each of the protective layers 13a and 13b is bonded and fixed to each of the main surface 1a and the back surface 1b of the flexible printed circuit board 100 with an adhesive (not shown) to protect the conductor surface from corrosion and oxidation. Thereby, environmental resistance can be improved.
 保護層13a、13bが設けられる場合は、主面1aおよび背面1bにおいて、プリント基板200との電気的接続に影響を及ぼさないように保護層13a、13bを設計する必要がある。たとえばACFのように、直径数μm~数十μmの導電粒子を配線間に挟み込んで電気的導通を得る場合、配線間における導電粒子の捕捉を妨げないように保護層13aを設計する必要がある。 When the protective layers 13a and 13b are provided, it is necessary to design the protective layers 13a and 13b so as not to affect the electrical connection with the printed circuit board 200 on the main surface 1a and the back surface 1b. For example, when conductive particles having a diameter of several μm to several tens of μm are sandwiched between wirings, such as ACF, it is necessary to design the protective layer 13a so as not to prevent the capturing of the conductive particles between the wirings. .
 実施の形態2.
 図4~図6に示されるように、実施の形態2におけるフレキシブルプリント基板100は、実施の形態1における電源回路部30および制御回路部40に代えて、電源回路部30と制御回路部40とが複合された複合回路部50を有する点において実施の形態1の構成と異なっている。
Embodiment 2. FIG.
As shown in FIGS. 4 to 6, the flexible printed circuit board 100 according to the second embodiment is replaced with the power supply circuit unit 30, the control circuit unit 40, and the power supply circuit unit 30 and the control circuit unit 40 according to the first embodiment. Is different from the configuration of the first embodiment in that it has a composite circuit unit 50 in which is combined.
 複合回路部50は、電源回路部30と制御回路部40とが複合された回路部であり、電源回路6と、補助電源回路7と、制御信号回路8と、電源回路用接続導体5とを有している。 The composite circuit unit 50 is a circuit unit in which the power supply circuit unit 30 and the control circuit unit 40 are combined, and includes the power supply circuit 6, the auxiliary power supply circuit 7, the control signal circuit 8, and the power supply circuit connection conductor 5. Have.
 補助電源回路7は電源回路6だけではなく、制御信号回路8にも対向するように背面1bに形成されている。すなわち、実施の形態1におけるダミー回路9が省略され、補助電源回路7の導体幅が制御信号回路8の背面側まで広げられている。 The auxiliary power circuit 7 is formed on the back surface 1 b so as to face not only the power circuit 6 but also the control signal circuit 8. That is, the dummy circuit 9 in the first embodiment is omitted, and the conductor width of the auxiliary power circuit 7 is extended to the back side of the control signal circuit 8.
 補助電源回路7は、スルーホール5a内を埋め込む電源回路用接続導体5により電源回路6と電気的に接続されている。 The auxiliary power circuit 7 is electrically connected to the power circuit 6 by a power circuit connecting conductor 5 that fills the through hole 5a.
 なお上記以外の本実施の形態の構成は、実施の形態1の構成とほぼ同じであるため同一の要素については同一の符号を付し、その説明を繰り返さない。 Since the configuration of the present embodiment other than the above is substantially the same as the configuration of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is not repeated.
 本実施の形態においては、ダミー回路9が省略され、補助電源回路7の導体幅が制御信号回路8の背面側まで広げられている。このような構造とした結果、補助電源回路7の断面積を実施の形態1よりも大きく確保することができる。これにより、放熱特性をより向上させたフレキシブルプリント基板100を実現することができる。 In the present embodiment, the dummy circuit 9 is omitted, and the conductor width of the auxiliary power circuit 7 is extended to the back side of the control signal circuit 8. As a result of such a structure, the auxiliary power circuit 7 can have a larger cross-sectional area than that of the first embodiment. Thereby, the flexible printed circuit board 100 which further improved the heat dissipation characteristic can be realized.
 一般に電源回路に関わる配線の温度上昇は、回路の電流値と抵抗値とに起因するジュール熱による発熱が原因となる。しかし、回路を構成している部材の温度は、部材が置かれている環境、すなわち部材周辺の外気温や放熱性に左右されるため、部位によって異なる。回路の放熱性がよい部位は速やかに熱が逃げるため温度は低く抑えられる。一方、回路の放熱性が悪い部位は熱が蓄積するため温度が高くなる。 Generally, the temperature rise of the wiring related to the power supply circuit is caused by heat generation due to Joule heat caused by the current value and resistance value of the circuit. However, the temperature of the member constituting the circuit depends on the environment in which the member is placed, that is, the outside air temperature around the member and the heat dissipation, and therefore varies depending on the part. Since the heat escapes quickly in the part with good heat dissipation of the circuit, the temperature is kept low. On the other hand, the temperature of the portion where the heat dissipation property of the circuit is bad increases because heat accumulates.
 フレキシブルプリント基板のようにプリント基板間を接続する目的で空中配線されるような場合にあっては、プリント基板と直接つながっているフレキシブルプリント基板の両端付近と、空中に架かっている部分では放熱性が異なるため通電中の温度も異なる。プリント基板と接続されるフレキシブルプリント基板の両端付近にあっては温度が低く、空中に架かっている部分では温度が高くなる。 When wiring in the air for the purpose of connecting between printed circuit boards, such as a flexible printed circuit board, heat dissipation is performed near both ends of the flexible printed circuit board directly connected to the printed circuit board and in the air. Therefore, the temperature during energization is different. The temperature is low in the vicinity of both ends of the flexible printed circuit board connected to the printed circuit board, and the temperature is high in the portion suspended in the air.
 プリント基板と接続される部分では、フレキシブルプリント基板の発熱はプリント基板のパッド電極やスルーホールなどの金属部分を通じて基板外のたとえば金属筺体などに速やかに放熱される。一方、空中に架かっている部分では、フレキシブルプリント基板の周辺は熱の絶縁体である空気である。またフレキシブルプリント基板を構成する部材自体も金属配線部以外は前述したようなポリイミドフィルム基材およびエポキシ樹脂系接着剤またはアクリル樹脂系接着剤で構成されているため熱伝導率が大幅に低い(両者とも0.2W/mK程度)。このため、放熱経路としてはフレキシブルプリント基板上の金属導体を伝わってプリント基板に放熱することになる。しかし、この場合、伝熱距離が長くなるため熱抵抗が大きくなって放熱性が不十分となる場合が少なくない。 In the portion connected to the printed circuit board, the heat generated by the flexible printed circuit board is quickly radiated to a metal casing or the like outside the printed circuit board through a metal part such as a pad electrode or a through hole of the printed circuit board. On the other hand, in the part suspended in the air, the periphery of the flexible printed circuit board is air which is a thermal insulator. Moreover, since the members constituting the flexible printed circuit board are composed of the polyimide film base and the epoxy resin adhesive or the acrylic resin adhesive as described above except for the metal wiring portion, the thermal conductivity is significantly low (both Both are about 0.2W / mK). For this reason, as a heat dissipation path, the heat is transmitted to the printed circuit board through the metal conductor on the flexible printed circuit board. However, in this case, since the heat transfer distance becomes long, the thermal resistance becomes large and the heat radiation performance is often insufficient.
 そこで本実施の形態では、補助電源回路7の断面積が増加されることにより、ジュール熱の発生が抑えられている。また補助電源回路7の表面積を増加させて補助電源回路7を放熱板として機能させることにより空中への熱放散が容易とされている。これにより、フレキシブルプリント基板100全体の温度上昇が低減される。 Therefore, in the present embodiment, the generation of Joule heat is suppressed by increasing the cross-sectional area of the auxiliary power circuit 7. Further, by increasing the surface area of the auxiliary power circuit 7 and causing the auxiliary power circuit 7 to function as a heat sink, heat dissipation into the air is facilitated. Thereby, the temperature rise of the whole flexible printed circuit board 100 is reduced.
 なお電源回路6の導体幅は、電源回路用接続導体5を接続するのに必要な最低限の幅を有していればよい。また電源回路6は、必要であればプリント基板との接続面積を電源回路6の長手方向に増すこともできるため、制御信号回路8の高密度配線の配線エリアを阻害することはない。 Note that the conductor width of the power supply circuit 6 only needs to have a minimum width necessary to connect the power supply circuit connection conductor 5. Further, the power supply circuit 6 can increase the connection area with the printed circuit board in the longitudinal direction of the power supply circuit 6 if necessary, so that the high-density wiring area of the control signal circuit 8 is not hindered.
 本実施の形態に示すような構造により、温度上昇を低く抑えることで高い信頼性を維持しながら大電流容量を確保できるフレキシブルプリント基板100を実現することができる。 With the structure as shown in this embodiment, it is possible to realize the flexible printed circuit board 100 that can secure a large current capacity while maintaining high reliability by suppressing the temperature rise low.
 また、本実施の形態におけるフレキシブルプリント基板100は、図1に示すフレキシブルプリント基板100の断面構造と同じようにフレキシブルプリント基板100の面内での厚さが均一である。したがって、本実施の形態においても実施の形態1と同様に、コネクタ、ACFまたははんだを用いた接続において、高信頼性の接続を得ることができる。 Further, the flexible printed circuit board 100 in the present embodiment has a uniform thickness in the plane of the flexible printed circuit board 100 as in the cross-sectional structure of the flexible printed circuit board 100 shown in FIG. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.
 実施の形態3.
 図7~図10に示されるように、本実施の形態におけるフレキシブルプリント基板100は、実施の形態1における制御回路部40に代えて、電源回路部30と制御回路部40とが複合された複合回路部60を有する点において実施の形態1の構成と異なっている。
Embodiment 3 FIG.
As shown in FIGS. 7 to 10, the flexible printed circuit board 100 in the present embodiment is a composite in which a power supply circuit unit 30 and a control circuit unit 40 are combined instead of the control circuit unit 40 in the first embodiment. The configuration differs from that of the first embodiment in that the circuit portion 60 is provided.
 複合回路部60においては、ベースフィルム1の主面1aに、複数の制御信号回路8と、複数の電源回路端子10とが形成されている。また複合回路部60においては、ベースフィルム1の背面1bに、補助電源回路7が形成されている。 In the composite circuit section 60, a plurality of control signal circuits 8 and a plurality of power circuit terminals 10 are formed on the main surface 1 a of the base film 1. In the composite circuit unit 60, the auxiliary power circuit 7 is formed on the back surface 1 b of the base film 1.
 複数の制御信号回路8は、主面1a上において複数の制御信号回路8の長手方向が互いに並走するように直線状に延在している。複数の電源回路端子10は、主面1a上において制御信号回路8の長手方向の延長線上に位置しており、制御信号回路8の長手方向の一方側と他方側との双方に配置されている。複合回路部60における複数の補助電源回路7は、背面1b上において互いに並走するように直線状に延在している。複数の電源回路6の各々は、電源回路用接続導体5により補助電源回路7に電気的に接続されている。 The plurality of control signal circuits 8 linearly extend on the main surface 1a so that the longitudinal directions of the plurality of control signal circuits 8 run in parallel with each other. The plurality of power supply circuit terminals 10 are located on an extension line in the longitudinal direction of the control signal circuit 8 on the main surface 1a, and are arranged on both one side and the other side in the longitudinal direction of the control signal circuit 8. . The plurality of auxiliary power supply circuits 7 in the composite circuit unit 60 extend linearly so as to run parallel to each other on the back surface 1b. Each of the plurality of power supply circuits 6 is electrically connected to the auxiliary power supply circuit 7 by a power supply circuit connection conductor 5.
 複数の電源回路用接続導体5の各々は、ベースフィルム1に形成されたスルーホール5aを埋め込むように形成されている。 Each of the plurality of power supply circuit connection conductors 5 is formed so as to embed a through hole 5a formed in the base film 1.
 なお上記以外の本実施の形態の構成は、実施の形態1の構成とほぼ同じであるため同一の要素については同一の符号を付し、その説明を繰り返さない。 Since the configuration of the present embodiment other than the above is substantially the same as the configuration of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is not repeated.
 複合回路部60は、電源回路部30の電流容量がフレキシブルプリント基板100に求められる電流容量に対して不足する場合に設けられる。本実施の形態においてもフレキシブルプリント基板100の電流容量の大半を担うのは電源回路部30である。しかし、複合回路部60に設けられた増設構造により電源回路部30の電流容量を補助的に増大させることができる。 The composite circuit section 60 is provided when the current capacity of the power supply circuit section 30 is insufficient with respect to the current capacity required for the flexible printed circuit board 100. Also in the present embodiment, the power supply circuit unit 30 bears most of the current capacity of the flexible printed circuit board 100. However, the current capacity of the power supply circuit unit 30 can be supplementarily increased by the additional structure provided in the composite circuit unit 60.
 本実施の形態の構成は、実施の形態2で述べた補助電源回路7の機能とは異なり、純粋に接続部の接触面積を増すことを目的にした構造である。 Unlike the function of the auxiliary power supply circuit 7 described in the second embodiment, the configuration of the present embodiment is a structure that is purely intended to increase the contact area of the connection portion.
 このような構造を必要とする接続形態は、たとえばACFを用いて回路間を接続する場合において接続部の抵抗が数Ω程度まで上昇してしまい大電流を通電した時に接続部で生じるジュール熱による発熱が無視できない場合において効果を発揮する。また、このような構造を必要とする接続形態は、たとえば接続部を低インピーダンスで接続しないと回路的に問題が生じるようなアナログ回路においても効果を発揮する。 A connection configuration that requires such a structure is caused by Joule heat generated at the connection portion when the resistance of the connection portion rises to about several Ω when a circuit is connected using, for example, ACF, and a large current is applied. Effective when heat generation cannot be ignored. Moreover, the connection form which requires such a structure is effective even in an analog circuit in which a problem occurs in a circuit unless the connection portion is connected with low impedance.
 ここではフレキシブルプリント基板100(図7~図10)とプリント基板200(図11)とをACFを用いて接続する場合を例にとって、図9および図11を参照しながら説明する。図11の点線は、フレキシブルプリント基板100とプリント基板200とを接続した際に、前記フレキシブルプリント基板100がプリント基板200に重なる部分を表している。 Here, an example in which the flexible printed circuit board 100 (FIGS. 7 to 10) and the printed circuit board 200 (FIG. 11) are connected using an ACF will be described with reference to FIGS. 9 and 11. FIG. A dotted line in FIG. 11 represents a portion where the flexible printed circuit board 100 overlaps the printed circuit board 200 when the flexible printed circuit board 100 and the printed circuit board 200 are connected.
 図11に示されるように、プリント基板200は、基板201と、中心導体202と、接地導体204と、電源回路206と、制御回路端子208と、電源回路端子210と、下層配線215と、接続導体205とを主に有している。 As shown in FIG. 11, the printed circuit board 200 includes a substrate 201, a center conductor 202, a ground conductor 204, a power supply circuit 206, a control circuit terminal 208, a power supply circuit terminal 210, and a lower layer wiring 215. It mainly has a conductor 205.
 基板201は、互いに異なる仕様の複数の電気回路の形成領域を有している。複数の電気回路形成領域は、たとえば高周波回路部220と、電源回路部230と、複合回路部260とを有している。 The substrate 201 has a plurality of electric circuit formation regions having different specifications. The plurality of electric circuit formation regions include, for example, a high-frequency circuit unit 220, a power supply circuit unit 230, and a composite circuit unit 260.
 高周波回路部220においては、基板201の表面に中心導体202と、接地導体204とが形成されている。たとえば2つの接地導体204が1つの中心導体202を挟み込んでいる。また中心導体202と2つの接地導体204とは互いに並走するように直線状に延びている。 In the high-frequency circuit unit 220, a center conductor 202 and a ground conductor 204 are formed on the surface of the substrate 201. For example, two ground conductors 204 sandwich one central conductor 202. The center conductor 202 and the two ground conductors 204 extend linearly so as to run in parallel with each other.
 電源回路部230においては、基板201の表面に複数の電源回路206が形成されている。複数の電源回路206の各々は、互いに並走するように直線状に延びている。また複数の電源回路206の各々は、中心導体202および接地導体204と並走している。 In the power supply circuit unit 230, a plurality of power supply circuits 206 are formed on the surface of the substrate 201. Each of the plurality of power supply circuits 206 extends linearly so as to run in parallel with each other. Each of the plurality of power supply circuits 206 is parallel to the center conductor 202 and the ground conductor 204.
 複合回路部260においては、基板201の表面に複数の制御回路端子208と、複数の電源回路端子210とが形成されている。複数の制御回路端子208は、複数の電源回路206が並ぶ方向と同じ方向に、互いに並んで配置されている。また複数の電源回路端子210は、複数の電源回路206が並ぶ方向と同じ方向に、互いに並んで配置されている。 In the composite circuit section 260, a plurality of control circuit terminals 208 and a plurality of power supply circuit terminals 210 are formed on the surface of the substrate 201. The plurality of control circuit terminals 208 are arranged side by side in the same direction as the direction in which the plurality of power supply circuits 206 are arranged. The plurality of power supply circuit terminals 210 are arranged side by side in the same direction as the direction in which the plurality of power supply circuits 206 are arranged.
 複数の電源回路端子210の各々は、電源回路206の各々に下層配線215により電気的に接続されている。複数の下層配線215の各々は、基板201の裏面において電源回路部230から複合回路部260へ延びている。下層配線215は、接続導体205により電源回路206に電気的に接続されている。また下層配線215は、接続導体205により電源回路端子210に電気的に接続されている。 Each of the plurality of power supply circuit terminals 210 is electrically connected to each of the power supply circuits 206 by a lower layer wiring 215. Each of the plurality of lower layer wirings 215 extends from the power supply circuit unit 230 to the composite circuit unit 260 on the back surface of the substrate 201. The lower layer wiring 215 is electrically connected to the power supply circuit 206 by the connection conductor 205. The lower layer wiring 215 is electrically connected to the power supply circuit terminal 210 by the connection conductor 205.
 制御回路端子208は接続導体205により、基板201の裏面に形成された下層配線(図示せず)に電気的に接続されている。 The control circuit terminal 208 is electrically connected to a lower layer wiring (not shown) formed on the back surface of the substrate 201 by a connection conductor 205.
 なお接続導体205は、基板201に設けられたスルーホール205a内を埋め込むように形成されている。 The connection conductor 205 is formed so as to be embedded in the through hole 205a provided in the substrate 201.
 電源回路6(図9)は、対向する電源回路206(図11)との間にACFの導電粒子を挟み込むことで電気的に導通する。対向する回路間の接続面積を拡大するには、その対向する回路それぞれの導体幅を拡大する方法がある。しかし、この場合、フレキシブルプリント基板100およびプリント基板200の幅が大きくなり、製品全体の小型化を妨げる要因となる。 The power supply circuit 6 (FIG. 9) is electrically connected by sandwiching conductive particles of ACF between the power supply circuit 206 (FIG. 11) facing the power supply circuit 6 (FIG. 9). In order to increase the connection area between the opposing circuits, there is a method of increasing the conductor width of each of the opposing circuits. However, in this case, the widths of the flexible printed circuit board 100 and the printed circuit board 200 are increased, which is a factor that hinders downsizing of the entire product.
 そこで図7~図10に示されるようにフレキシブルプリント基板100には複合回路部60が設けられ、図11に示されるようにプリント基板200には複合回路部60の主面1aのパターンに対応した制御回路端子208と電源回路端子210とが設けられている。電源回路端子210は接続導体205によって下層配線215に電気的に接続され、下層配線215は接続導体205によって電源回路206に電気的に接続されている。これにより電源回路端子210は電源回路206に電気的に接続されている。制御回路端子208も同じく接続導体205および図示しない下層配線によってプリント基板200の面内に配線されている。 7 to 10, the flexible printed circuit board 100 is provided with a composite circuit portion 60, and the printed circuit board 200 corresponds to the pattern of the main surface 1 a of the composite circuit portion 60 as shown in FIG. 11. A control circuit terminal 208 and a power circuit terminal 210 are provided. The power supply circuit terminal 210 is electrically connected to the lower layer wiring 215 by the connection conductor 205, and the lower layer wiring 215 is electrically connected to the power supply circuit 206 by the connection conductor 205. As a result, the power supply circuit terminal 210 is electrically connected to the power supply circuit 206. The control circuit terminal 208 is also wired in the plane of the printed circuit board 200 by the connection conductor 205 and a lower layer wiring (not shown).
 上記の構造により、プリント基板200の電源回路206を通電する電流は、以下の2つの経路に分かれる。すなわち、接続導体205、下層配線215および電源回路端子210を通じてフレキシブルプリント基板100の複合回路部60に通電する経路と、プリント基板200の電源回路206およびフレキシブルプリント基板100の電源回路部30に通電する経路である。 With the above structure, the current flowing through the power supply circuit 206 of the printed circuit board 200 is divided into the following two paths. That is, a path for energizing the composite circuit unit 60 of the flexible printed circuit board 100 through the connection conductor 205, the lower layer wiring 215, and the power circuit terminal 210, and a power circuit 206 for the printed circuit board 200 and the power circuit unit 30 of the flexible printed circuit board 100 are energized. It is a route.
 この結果、本実施の形態におけるフレキシブルプリント基板100はACF接続部の面積を増加させることができるため、接続部の抵抗を下げることができる。 As a result, since the flexible printed circuit board 100 according to the present embodiment can increase the area of the ACF connection portion, the resistance of the connection portion can be reduced.
 また、電流が通じる経路を分散させることで、主面1aの電源回路部30の電源回路6が何らかの原因で導通不良となった場合においても冗長回路として使用することもできる。したがって、本実施の形態においても実施の形態1と同様に、コネクタ、ACFまたははんだを用いた接続において、高信頼性の接続を得ることができる。 Also, by distributing the path through which the current passes, the power supply circuit 6 of the power supply circuit unit 30 on the main surface 1a can be used as a redundant circuit even when conduction failure occurs for some reason. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.
 また、本実施の形態におけるフレキシブルプリント基板100は、図1に示すフレキシブルプリント基板100の断面構造と同じようにフレキシブルプリント基板面内での厚さが均一である。したがって、本実施の形態においても実施の形態1と同様に、コネクタ、ACFまたははんだを用いた接続において、高信頼性の接続を得ることができる。 In addition, the flexible printed circuit board 100 in the present embodiment has a uniform thickness in the surface of the flexible printed circuit board as in the cross-sectional structure of the flexible printed circuit board 100 shown in FIG. Therefore, also in the present embodiment, as in the first embodiment, a highly reliable connection can be obtained in the connection using the connector, the ACF, or the solder.
 今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 The embodiment disclosed this time should be considered as illustrative in all points and 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.
 1 ベースフィルム、1a 主面、1b 背面、2,202 中心導体、3 背面接地導体、4,204 接地導体、5,205 接続導体、5a スルーホール、6,206 電源回路、7 補助電源回路、8 制御信号回路、9 ダミー回路、10,210 電源回路端子、11 樹脂、12導電粒子、13a,13b保護層、20,220 高周波回路部、30,230 電源回路部、40 制御回路部、50,60,260 複合回路部、100 フレキシブルプリント基板、200 プリント基板、201 基板、208 制御回路端子、215 下層配線。 1 Base film, 1a main surface, 1b back surface, 2,202 center conductor, 3 back ground conductor, 4,204 ground conductor, 5,205 connecting conductor, 5a through hole, 6,206 power circuit, 7 auxiliary power circuit, 8 Control signal circuit, 9 dummy circuit, 10, 210 power circuit terminal, 11 resin, 12 conductive particles, 13a, 13b protective layer, 20, 220 high frequency circuit section, 30, 230 power circuit section, 40 control circuit section, 50, 60 , 260 composite circuit section, 100 flexible printed circuit board, 200 printed circuit board, 201 circuit board, 208 control circuit terminal, 215 lower layer wiring.

Claims (9)

  1.  互いに対向する第1面および第2面を有し、かつ絶縁体よりなるベースフィルムと、
     前記ベースフィルムの前記第1面に形成された複数の第1導体と、
     前記ベースフィルムの前記第2面に形成された複数の第2導体と、
     前記ベースフィルムを貫通し、かつ前記複数の第1導体のそれぞれの一部と前記複数の第2導体のそれぞれの一部とを電気的に接続する複数の接続導体とを備え、
     前記複数の第2導体の各々の膜厚は前記複数の第1導体の各々の膜厚よりも厚い、フレキシブルプリント基板。
    A base film having a first surface and a second surface facing each other and made of an insulator;
    A plurality of first conductors formed on the first surface of the base film;
    A plurality of second conductors formed on the second surface of the base film;
    A plurality of connection conductors penetrating the base film and electrically connecting each of the plurality of first conductors and each of the plurality of second conductors;
    The flexible printed circuit board, wherein each of the plurality of second conductors is thicker than each of the plurality of first conductors.
  2.  前記複数の第1導体および前記複数の第2導体は、高周波回路部と、電源回路部と、制御回路部とを構成する、請求項1に記載のフレキシブルプリント基板。 The flexible printed circuit board according to claim 1, wherein the plurality of first conductors and the plurality of second conductors constitute a high-frequency circuit unit, a power supply circuit unit, and a control circuit unit.
  3.  前記高周波回路部は、中心導体を含み、
     前記電源回路部は、電源回路と、補助電源回路とを含み、
     前記複数の第1導体は、前記中心導体と前記電源回路とを含み、
     前記複数の第2導体は、前記補助電源回路を含む、請求項2に記載のフレキシブルプリント基板。
    The high-frequency circuit unit includes a center conductor,
    The power supply circuit unit includes a power supply circuit and an auxiliary power supply circuit,
    The plurality of first conductors include the center conductor and the power supply circuit,
    The flexible printed circuit board according to claim 2, wherein the plurality of second conductors include the auxiliary power supply circuit.
  4.  前記高周波回路部における前記第1導体の膜厚、前記第2導体の膜厚および前記ベースフィルムの膜厚の合計の膜厚は、前記電源回路部における前記第1導体の膜厚、前記第2導体の膜厚および前記ベースフィルムの膜厚の合計の膜厚と等しく、かつ前記制御回路部における前記第1導体の膜厚、前記第2導体の膜厚および前記ベースフィルムの膜厚の合計の膜厚と等しい、請求項2に記載のフレキシブルプリント基板。 The total film thickness of the first conductor, the second conductor, and the base film in the high-frequency circuit section is the thickness of the first conductor in the power circuit section, the second Equal to the total film thickness of the conductor and the base film, and the total thickness of the first conductor, the second conductor and the base film in the control circuit unit. The flexible printed circuit board of Claim 2 equal to a film thickness.
  5.  前記複数の接続導体は、前記高周波回路部において互いに隣り合う2つの高周波回路用接続導体を含み、
     前記2つの高周波回路用接続導体の最短距離は前記高周波回路部を伝送する電磁波の波長の4分の1以下である、請求項2に記載のフレキシブルプリント基板。
    The plurality of connection conductors include two high-frequency circuit connection conductors adjacent to each other in the high-frequency circuit unit,
    The flexible printed circuit board according to claim 2, wherein a shortest distance between the connection conductors for the two high-frequency circuits is equal to or less than a quarter of a wavelength of an electromagnetic wave transmitted through the high-frequency circuit unit.
  6.  前記複数の接続導体は、前記電源回路部において前記電源回路と前記補助電源回路とを電気的に接続する電源回路用接続導体を含み、
     前記電源回路用接続導体の断面積は、前記補助電源回路の断面積以上である、請求項3に記載のフレキシブルプリント基板。
    The plurality of connection conductors include a power supply circuit connection conductor for electrically connecting the power supply circuit and the auxiliary power supply circuit in the power supply circuit unit,
    The flexible printed circuit board according to claim 3, wherein a cross-sectional area of the connection conductor for power supply circuit is equal to or greater than a cross-sectional area of the auxiliary power supply circuit.
  7.  前記制御回路部は、制御信号回路を含み、
     前記電源回路部は、電源回路と、補助電源回路とを含み、
     前記複数の第1導体は、前記制御信号回路と、前記電源回路とを含み、
     前記複数の第2導体は、前記補助電源回路を含み、
     前記補助電源回路は、前記電源回路および前記制御信号回路の双方と対向している、請求項2に記載のフレキシブルプリント基板。
    The control circuit unit includes a control signal circuit,
    The power supply circuit unit includes a power supply circuit and an auxiliary power supply circuit,
    The plurality of first conductors includes the control signal circuit and the power supply circuit,
    The plurality of second conductors include the auxiliary power supply circuit,
    The flexible printed circuit board according to claim 2, wherein the auxiliary power supply circuit faces both the power supply circuit and the control signal circuit.
  8.  前記電源回路の長手方向と前記制御信号回路の長手方向とが互いに並走するように前記電源回路と前記制御信号回路とが並んでいる、請求項7に記載のフレキシブルプリント基板。 The flexible printed circuit board according to claim 7, wherein the power supply circuit and the control signal circuit are arranged so that a longitudinal direction of the power supply circuit and a longitudinal direction of the control signal circuit run in parallel with each other.
  9.  前記電源回路は、前記制御信号回路の長手方向の延長線上に位置している、請求項7に記載のフレキシブルプリント基板。 The flexible printed circuit board according to claim 7, wherein the power supply circuit is located on an extension line in a longitudinal direction of the control signal circuit.
PCT/JP2017/019859 2016-06-09 2017-05-29 Flexible printed board WO2017212966A1 (en)

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WO2023095386A1 (en) * 2021-11-29 2023-06-01 日立Astemo株式会社 Electronic device

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