JP2010153540A - Printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board for preventing change in the characteristic impedance of a conductor pattern. <P>SOLUTION: In the printed circuit board, a base insulating layer 11, a wiring cover insulating layer 12, and a ground cover insulating layer are bent with the wiring cover insulating layer 12 placed in the internal side. A flat-plate spacer 20 is inserted between wiring patterns 2 provided opposed with each other. In this case, the thickness of the spacer 20 is adjusted to maintain a distance of the wiring cover insulating layers 12 provided opposed with each other to ≥0.5 mm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printed wiring board.

  Many flexible printed wiring boards (for example, refer to Patent Document 1) are used for electronic devices and electric devices. Hereinafter, the flexible printed wiring board is abbreviated as a printed wiring board.

  FIG. 13 is an external perspective view showing a conventional printed wiring board. A printed wiring board 700 shown in FIG. 13 has a base insulating layer 701 and a long conductor pattern 702 provided on the base insulating layer 701. An insulating cover layer (not shown) is formed on the insulating base layer 701 so as to cover the conductor pattern 702.

The printed wiring board 700 having such a configuration is excellent in bendability and can be easily bent at an arbitrary position as shown in FIG. Therefore, conventionally, the printed wiring board 700 has been effectively used in a bent portion such as a hinge portion of an electronic device.
JP 2002-111138 A

  However, as shown in FIG. 13, when a part of the printed wiring board 700 is folded in two, the conductor patterns 702 face each other in the folded direction. In this case, the electromagnetic fields interfere with each other in the portion of the conductor pattern 702 facing each other, whereby the characteristic impedance of the conductor pattern 702 changes depending on the position, and the transmission efficiency of the electric signal in the conductor pattern 702 is lowered.

  The objective of this invention is providing the printed wiring board which can prevent the change of the characteristic impedance of a conductor pattern.

  (1) A printed wiring board according to a first aspect of the present invention includes a base insulating layer, a wiring pattern formed on one surface of the base insulating layer, and a first formed on one surface of the base insulating layer so as to cover the wiring pattern. The base insulating layer and the first insulating cover layer are bent so that at least a part of the wiring patterns face each other, and the distance between the facing wiring pattern parts is 0.5 mm. Spacers are arranged between the opposing wiring pattern portions so as to be maintained as described above.

  In the printed wiring board, a wiring pattern is formed on one surface of the base insulating layer, and a first insulating cover layer is formed on one surface of the base insulating layer so as to cover the wiring pattern. The base insulating layer and the first cover insulating layer are bent so that at least some of the wiring patterns face each other. Spacers are arranged between the facing wiring pattern portions so that the distance between the facing wiring pattern portions is maintained at 0.5 mm or more.

  In this case, the distance between the facing wiring pattern portions is maintained at 0.5 mm or more, thereby preventing the electromagnetic fields from interfering with each other at the facing wiring pattern portions. As a result, the characteristic impedance of the wiring pattern is prevented from changing depending on the position, and the transmission efficiency of the electrical signal is prevented from being lowered.

  (2) The spacer may have a relative dielectric constant of 1.1 or less.

  In this case, since the relative dielectric constant of the spacer is close to the relative dielectric constant of air, the capacitance value of the portion of the opposing wiring pattern is reduced. Thereby, the interference of the electromagnetic field in the part of the wiring pattern which opposes can be prevented more fully.

  (3) The spacer may be formed of a porous material.

  In this case, the relative dielectric constant of the spacer can be easily reduced. Thereby, the interference of the electromagnetic field in the part of the opposing wiring pattern can be sufficiently prevented at low cost.

  (4) The insulating base layer and the insulating first cover layer are bent inwardly of the insulating first cover layer, and the spacer is between the portions of the wiring pattern facing each other so as to be sandwiched by the insulating first cover layer. May be arranged.

  In this case, at least a part of the first insulating cover layer is opposed between the portions of the opposing wiring patterns. The distance between the opposing first cover insulating layer portions is equal to the thickness of the spacer. Thereby, by adjusting the thickness of the spacer, the distance between the opposing wiring pattern portions can be adjusted to 0.5 mm or more easily and reliably.

  (5) You may further provide the ground layer formed in the other surface of a base insulating layer, and the 2nd cover insulating layer formed on the other surface of a base insulating layer so that a ground layer may be covered.

  In this case, the potential of the wiring pattern can be stably maintained by the ground layer. Further, when the base insulating layer and the first and second cover insulating layers are bent with the first cover insulating layer inside, the wiring pattern is located inside the ground layer. As a result, the ground layer can prevent external high frequency noise from affecting the wiring pattern.

  (6) The insulating base layer and the insulating first cover layer may be bent inwardly of the insulating base layer, and the spacer may be disposed between the opposing wiring pattern portions so as to be sandwiched by the insulating base layer. .

  In this case, at least a part of the base insulating transmission is opposed between the portions of the opposing wiring patterns. The distance between the opposing base insulating layer portions is equal to the thickness of the spacer. Thereby, by adjusting the thickness of the spacer, the distance between the opposing wiring pattern portions can be adjusted to 0.5 mm or more easily and reliably.

  (7) A method for manufacturing a printed wiring board according to a second invention includes a step of forming a wiring pattern on one surface of the base insulating layer, and a first insulating cover layer on one surface of the base insulating layer so as to cover the wiring pattern. The distance between the step of forming the base insulating layer and the first cover insulating layer so that at least a part of the wiring pattern faces each other, and the distance between the facing wiring pattern portions is 0.5 mm or more And a step of arranging a spacer between the portions of the wiring patterns facing each other so as to be maintained.

  According to the manufacturing method, the distance between the facing wiring pattern portions is maintained at 0.5 mm or more by the spacer. This prevents the electromagnetic fields from interfering with each other at the opposing wiring pattern portions. As a result, the characteristic impedance of the wiring pattern is prevented from changing depending on the position, and the transmission efficiency of the electrical signal is prevented from being lowered.

  According to the present invention, it is possible to prevent electromagnetic fields from interfering with each other at the portions of the opposing wiring patterns. As a result, the characteristic impedance of the wiring pattern is prevented from changing depending on the position, and the transmission efficiency of the electrical signal is prevented from being lowered.

  Hereinafter, a flexible printed wiring board according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the flexible printed wiring board is abbreviated as a printed wiring board.

(1) First Embodiment (1-1) Configuration of Printed Wiring Board FIG. 1 is an external perspective view of a printed wiring board according to the first embodiment of the present invention.

  As shown in FIG. 1, the printed wiring board 100 includes a long base insulating layer 11. A plurality (two in this example) of wiring patterns 2 are formed on one surface of the base insulating layer 11.

  As will be described later, a wiring cover insulating layer is formed on one surface of the base insulating layer 11 so as to cover the wiring pattern 2, and a ground layer and a ground cover insulating layer are formed on the other surface of the base insulating layer 11. Has been. Hereinafter, the base insulating layer 11, the cover insulating layer, and the ground cover insulating layer are collectively referred to as an insulating layer.

  On one surface of the base insulating layer 11 (on the wiring cover insulating layer), a connector 31 is provided in the vicinity of one end thereof. One end of the wiring pattern 2 is electrically connected to the connector 31. A connector 32 is provided on the other surface of the base insulating layer 11 (on the ground cover insulating layer) near the other end. The other end of the wiring pattern 2 is electrically connected to the connector 32.

  The insulating layer is bent at a predetermined position. Thereby, a part of wiring pattern 2 opposes. A flat spacer 20 is inserted between the opposing wiring pattern 2 portions.

  FIG. 2 is a plan view of the printed wiring board 100 in a state where the insulating layer is not bent. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB in FIG. The configuration of the printed wiring board 100 will be specifically described with reference to FIGS.

  As shown in FIG. 2, the wiring pattern 2 is formed along the length direction of the base insulating layer 11. A linear bent portion B <b> 1 is provided at a predetermined position of the base insulating layer 11 along the width direction of the base insulating layer 11. The insulating base layer 11 is bent along the bent portion B1. In addition, a linear groove | channel may be formed in bending part B1, and a linear mark may be provided. If the base insulating layer 11 can be easily bent, nothing may be provided in the bent portion B1.

  As shown in FIGS. 3 and 4, a plurality of wiring patterns 2 are formed on one surface of the base insulating layer 11, and a wiring cover insulating layer 12 is formed on one surface of the base insulating layer 11 so as to cover the wiring pattern 2. ing. A ground layer 3 is formed on the other surface of the base insulating layer 11. A ground cover insulating layer 13 is formed on the other surface of the base insulating layer 11 so as to cover the ground layer 3. The wiring cover insulating layer 12 is an example of a first cover insulating layer, and the ground cover insulating layer 13 is an example of a second cover insulating layer.

  A connector 31 is provided on the wiring cover insulating layer 12. One end of each wiring pattern 2 is electrically connected to the connector 31. A connector 32 is provided on the ground cover insulating layer 13. A through hole 11 a is formed in the base insulating layer 11, and a through hole 3 a is formed in the ground layer 3. The other end of each wiring pattern 2 extends to the other surface side of the base insulating layer 11 through the through hole 11a and the through hole 3a, and is electrically connected to the connector 32. In the through hole 3 a of the ground layer 3, each wiring pattern 2 and the ground layer 3 are electrically insulated by the ground cover insulating layer 13.

  In FIG. 3, one through hole 11a and one through hole 3a are shown, but actually, a plurality of (two in this example) through holes 11a and a plurality of through holes 11a and a plurality of wiring patterns 2 are shown. A plurality of (two in this example) through-holes 3a are formed.

  Next, the printed wiring board 100 in a state where the insulating layer is bent will be described in detail. FIG. 5 is a cross-sectional view of the printed wiring board 100 in a state where the insulating layer is bent.

  As shown in FIG. 5, the base insulating layer 11, the wiring cover insulating layer 12, and the ground cover insulating layer 13 are bent with the wiring cover insulating layer 12 inside. In this case, a part of the wiring pattern 2 is opposed to the wiring cover insulating layer 12.

  A flat spacer 20 is inserted between the opposing wiring pattern 2 portions. The spacer 20 is made of a porous resin such as expanded polystyrene. As the spacer 20, a porous material such as a plate-like member having a honeycomb structure or a nonwoven fabric made of cotton or the like may be used. In this case, the relative dielectric constant of the spacer 20 can be easily reduced.

  The spacer 20 is disposed so that both surfaces thereof are in contact with the wiring cover insulating layer 12. In this case, the distance between the opposing wiring cover insulating layers 12 is maintained equal to the thickness of the spacer 20. Therefore, the distance D1 between the opposing wiring patterns 2 can be arbitrarily adjusted by adjusting the thickness of the spacer 20.

  In the present embodiment, the distance D1 between the opposing wiring patterns 2 is maintained by the spacer 20 at 0.5 mm or more. In this case, it is possible to prevent the electromagnetic fields from interfering with each other at the portion of the wiring pattern 2 facing each other. Thereby, the characteristic impedance of the wiring pattern 2 is prevented from changing depending on the position, and the transmission efficiency of the electric signal is prevented from being lowered.

  The relative dielectric constant of the spacer 20 is preferably 1.1 or less. In this case, since the relative permittivity of the spacer 20 is close to the relative permittivity of air, the capacitance value of the portion of the facing wiring pattern 2 becomes small. Thereby, the interference of the electromagnetic field in the part of the wiring pattern 2 which opposes can fully be prevented.

(1-2) Method for Manufacturing Printed Wiring Board Next, a method for manufacturing the printed wiring board 100 will be described. 6 and 7 are cross-sectional views illustrating the manufacturing process of the printed wiring board 100 according to the present embodiment. 6 and 7 show a manufacturing process in the cross section shown in FIG. 3 (cross section taken along line AA in FIG. 2). In the following description, the length corresponds to the size of the insulating base layer 11 in the length direction, and the width corresponds to the size of the insulating base layer 11 in the width direction.

  First, as shown in FIG. 6A, the base insulating layer 11 is prepared. The base insulating layer 11 is made of polyimide, for example. The thickness of the base insulating layer 11 is preferably 5 μm or more and 60 μm or less, and more preferably 8 μm or more and 30 μm or less. The width of the base insulating layer 11 is preferably 2 mm or more and 50 mm or less, and more preferably 3 mm or more and 30 mm or less.

  Next, as shown in FIG. 6B, a plurality of wiring patterns 2 are formed on one surface of the base insulating layer 11 by, for example, a semi-additive method. The wiring pattern 2 is made of, for example, copper. The thickness of the wiring pattern 2 is preferably 5 μm or more and 20 μm or less, and more preferably 8 μm or more and 18 μm or less. The width of the wiring pattern 2 is preferably 5 μm or more and 200 μm or less, and more preferably 10 μm or more and 100 μm or less. The interval between adjacent wiring patterns 2 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 100 μm or less.

  Note that the wiring pattern 2 may be formed by using another method such as a subtractive method instead of the semi-additive method.

  Next, as illustrated in FIG. 6C, a wiring cover insulating layer 12 is formed on one surface of the base insulating layer 11 so as to cover the wiring pattern 2. The wiring cover insulating layer 12 is made of polyimide, for example. The thickness of the wiring cover insulating layer 12 is preferably 8 μm or more and 30 μm or less, and more preferably 10 μm or more and 20 μm or less. The width of the wiring cover insulating layer 12 is preferably 2 mm or more and 50 mm or less, and more preferably 3 mm or more and 30 mm or less.

  Next, as shown in FIG. 6D, the ground layer 3 is formed on the other surface of the base insulating layer 11 by sputtering, for example, and the through hole 3a is formed in the ground layer 3 by etching, for example. The ground layer 3 is made of, for example, copper. The thickness of the ground layer 3 is preferably 5 μm or more and 20 μm or less, and more preferably 8 μm or more and 18 μm or less. The width of the ground layer 3 is preferably 2 mm or more and 50 mm or less, and more preferably 3 mm or more and 30 mm or less.

  Next, as shown in FIG. 6E, a ground cover insulating layer 13 is formed on the other surface of the base insulating layer 11 so as to cover the ground layer 3. The ground cover insulating layer 13 is made of polyimide, for example. The thickness of the ground cover insulating layer 13 is preferably 8 μm or more and 30 μm or less, and more preferably 10 μm or more and 20 μm or less. The width of the ground cover insulating layer 13 is preferably 2 mm or more and 50 mm or less, and more preferably 3 mm or more and 30 mm or less.

  Next, as shown in FIG. 7 (f), one end of each wiring pattern 2 is exposed on the wiring cover insulating layer 12, and the other end of each wiring pattern 2 is exposed on the ground cover insulating layer 13. . At this time, a through hole 11 a is formed in the base insulating layer 11.

  Next, as shown in FIG. 7G, the connector 31 is mounted on the wiring cover insulating layer 12 and electrically connected to one end of each wiring pattern 2, and the connector 32 is placed on the ground cover insulating layer 13. It is attached and electrically connected to the other end of each wiring pattern 2.

  Next, as illustrated in FIG. 7H, the spacer 20 is disposed in a predetermined region on the wiring cover insulating layer 12. The thickness of the spacer 20 is preferably not less than 0.5 mm and not more than 4 mm, and more preferably not less than 0.5 mm and not more than 2 mm. The length of the spacer 20 is preferably 0.1 mm or more and 50 mm or less, and more preferably 0.2 mm or more and 30 mm or less. The width of the spacer 20 is preferably 0.5 mm or more and 50 mm or less, and more preferably 1 mm or more and 20 mm or less. Note that the length and width of the spacer 20 may be equal to the length and width of the printed wiring board 100.

  Then, as shown in FIG. 7I, the base insulating layer 11, the wiring cover insulating layer 12, and the ground cover insulating layer 13 are bent along the bent portion B1 (FIG. 2). In this case, the distance between the opposing wiring patterns 2 is maintained at 0.5 mm or more by the spacer 20. Thereby, the printed wiring board 100 according to the present embodiment is completed.

(2) Examples and Comparative Examples (2-1) Examples 1-4
As Examples 1-4, the above printed wiring board 100 was produced.

  In Examples 1 to 4, the base insulating layer 11 had a thickness of 25 μm and a width of 10 mm. The thickness of each wiring pattern 2 was 12 μm, the width was 40 μm, and the interval between adjacent wiring patterns 2 was 40 μm. The wiring cover insulating layer 12 had a thickness of 15 μm and a width of 10 mm. The thickness of the ground layer 3 was 12 μm and the width was 8 mm. The thickness of the ground cover insulating layer 13 was 15 μm and the width was 10 mm.

  The length from one end of the insulating layer (the base insulating layer 11, the wiring cover insulating layer 12, and the ground cover insulating layer 13) to the bent portion B1 was 25 mm. That is, the length of the region of the insulating layer 25 mm that was bent and overlapped was set to 25 mm.

  In Examples 1 to 3, foamed polystyrene having a relative dielectric constant of 1.01 or more and 1.1 or less was used as the spacer 20. In Example 1, the thickness of the spacer 20 was 0.5 mm, in Example 2, the thickness of the spacer 20 was 1.0 mm, and in Example 3, the thickness of the spacer 20 was 2.0 mm. In Example 4, a non-woven fabric having a relative dielectric constant of 1.7 was used as the spacer 20. In Example 4, the thickness of the spacer 20 was 1.0 mm.

  In Examples 1 to 4, the width of the spacer 20 was 10 mm and the length was 24 mm.

(2-2) Comparative Examples 1 and 2
As Comparative Example 1, a printed wiring board 100 similar to that of Examples 1 to 3 was prepared except that the spacer 20 was not provided. In this case, the insulating layer 1 was bent so that the opposing wiring cover insulating layer 12 portions were in contact with each other.

  Moreover, as Comparative Example 2, a printed wiring board 100 similar to that of Examples 1 to 3 was manufactured except that the thickness of the spacer 20 was set to 0.3 mm.

(2-3) Evaluation In the printed wiring boards 100 of Examples 1 to 4 and Comparative Examples 1 and 2, the characteristic impedance of each wiring pattern 2 was measured by TDR (Time Domain Reflectometry). Further, the S parameter (passage characteristic) when a signal was input from the connector 31 was measured.

  As a reference example, the characteristic impedance and S parameter of each wiring pattern 2 were examined in a state where the insulating layer was not bent.

(2-3-1) Characteristic Impedance FIGS. 8 and 9 are diagrams showing measurement results of the characteristic impedance of each wiring pattern 2. FIG. 8 (a) shows the results of the reference example, FIGS. 8 (b) to 8 (e) show the results of Examples 1 to 4, and FIG. 9 (f) and FIG. 9 (g). Shows the results of Comparative Examples 1 and 2.

  8 and 9, the horizontal axis indicates the position on the wiring pattern 2 (distance from the connector 31), and the vertical axis indicates the characteristic impedance. In addition, the length of the wiring pattern 2 between the connector 31 and the connector 32 is about 100 mm.

  As shown in FIG. 8A, in the reference example, the characteristic impedance of each wiring pattern 2 was almost constant.

  As shown in FIGS. 8B to 8E, in Examples 1 to 4, the characteristic impedance was substantially constant at all positions of each wiring pattern 2 as in the reference example. On the other hand, as shown in FIGS. 9 (f) and 9 (g), in Comparative Examples 1 and 2, the characteristic impedance varied depending on the position of the wiring pattern 2.

  Thereby, when the distance between the wiring patterns 2 facing each other through the spacer 20 is adjusted to 0.5 mm or more, the characteristic impedance of each wiring pattern 2 varies depending on the position even if the insulating layer is bent. It was found that the characteristic impedance was almost constant at all positions of each wiring pattern 2.

  On the other hand, when the distance between the opposing wiring patterns 2 is smaller than 0.5 mm, the characteristic impedance of each wiring pattern 2 varies greatly depending on the position by bending the insulating layer, and depending on the position of each wiring pattern 2. It was found that the characteristic impedance varies.

  Moreover, in Examples 1-3, the difference with the reference example was smaller compared with Example 4. Thus, it was found that the change in characteristic impedance due to the bending of the insulating layer is further suppressed when the relative dielectric constant of the spacer 20 is 1.1 or less.

(2-3-2) S Parameter FIGS. 10 and 11 are diagrams showing measurement results of the pass characteristics (S ₂₁ ) of each wiring pattern 2. FIG. 10 (a) shows the results of the reference example, FIGS. 10 (b) to 10 (e) show the results of Examples 1 to 4, and FIGS. 11 (f) and 11 (g). Shows the results of Comparative Examples 1 and 2.

  10 and 11, the horizontal axis indicates the frequency, and the vertical axis indicates the gain. In this case, negative gain corresponds to loss.

  As shown in FIG. 10, in Examples 1-4, the passage characteristics hardly changed compared to the reference example. On the other hand, as shown in FIG. 11, in Comparative Examples 1 and 2, the pass characteristics greatly changed compared to the reference example, and the pass loss relatively increased compared to the reference example.

  From these results, when the distance between the wiring patterns 2 facing each other via the spacer 20 is adjusted to 0.5 mm or more, the distance between the wiring patterns 2 facing each other is smaller than 0.5 mm. It has been found that the transmission efficiency of electrical signals is improved.

  Moreover, in Examples 1-3, the difference with a reference example was smaller compared with Example 4, and the passage characteristic was more favorable. Accordingly, it has been found that when the dielectric constant of the spacer 20 is 1.1 or less, a decrease in electric signal transmission efficiency due to bending of the insulating layer is further suppressed.

(3) Second Embodiment Next, a second embodiment of the present invention will be described. FIG. 12 is a cross-sectional view illustrating a configuration of a printed wiring board according to the second embodiment. FIG. 12A shows a printed wiring board in a state where the insulating layer is not bent, and FIG. 12B shows a printed wiring board in a state where the insulating layer is bent.

  The printed wiring board 100a of FIG. 12 is different from the printed wiring board 100 of the first embodiment in the following points.

  In the printed wiring board 100a, the ground layer 3 and the ground cover insulating layer 13 are not formed. A connector 32 is provided on the wiring cover insulating layer 12. The other end of each wiring pattern 2 is electrically connected to the connector 32.

  The base insulating layer 11 and the wiring cover insulating layer 12 are bent with the base insulating layer 11 inside. In this case, part of the wiring pattern 2 is opposed to the base insulating layer 11. A spacer 20 is inserted between the opposing wiring pattern 2 portions. Both surfaces of the spacer 20 are in contact with the base insulating layer 11.

  In this case, the distance D2 between the opposing wiring patterns 2 is maintained at 0.5 mm or more by adjusting the thickness of the spacer 20. This prevents the electromagnetic fields from interfering with each other at the portion of the wiring pattern 2 facing each other. Therefore, the characteristic impedance of the wiring pattern 2 is prevented from changing depending on the position, and the transmission efficiency of the electric signal is prevented from being lowered.

(4) Other Embodiments In the second embodiment, the base insulating layer 11 and the wiring cover insulating layer 12 are bent with the base insulating layer 11 inside, but the wiring cover insulating layer 12 is inside. The base insulating layer 11 and the wiring cover insulating layer 12 may be bent. In this case, the spacer 20 is disposed so as to be sandwiched between the wiring cover insulating layers 12. A connector 32 is provided on the other surface of the base insulating layer 11 (the lower surface in FIG. 12A).

  In the first and second embodiments, polyimide is used as a material for the base insulating layer 11, the wiring cover insulating layer 12, and the ground cover insulating layer 13. However, the material is not limited to this, and polyethylene terephthalate, Other materials such as polyether nitrile, polyether sulfone may be used.

  Further, the material of the wiring pattern 2 and the ground layer 3 is not limited to copper, and other metals such as gold (Au) and aluminum, or alloys such as a copper alloy and an aluminum alloy may be used.

  The present invention can be used for a printed wiring board used in various electric devices or electronic devices.

1 is an external perspective view of a printed wiring board according to a first embodiment of the present invention. It is a top view of the printed wiring board in the state where the insulating layer is not bent. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is sectional drawing of the printed wiring board in the state by which the insulating layer was bent. It is sectional drawing which shows the manufacturing process of the printed wiring board which concerns on this Embodiment. It is sectional drawing which shows the manufacturing process of the printed wiring board which concerns on this Embodiment. It is a figure which shows the measurement result of the characteristic impedance of each wiring pattern. It is a figure which shows the measurement result of the characteristic impedance of each wiring pattern. It is a figure which shows the measurement result of the passage loss of each wiring pattern. It is a figure which shows the measurement result of the passage loss of each wiring pattern. It is sectional drawing which shows the structure of the printed wiring board which concerns on 2nd Embodiment. It is an external appearance perspective view which shows the conventional printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating layer 2 Wiring pattern 3 Ground layer 11 Base insulating layer 12 Wiring cover insulating layer 13 Ground cover insulating layer 20 Spacer 31, 32 Connector 100, 100a Printed wiring board B1 Bending part

Claims (7)

A base insulating layer;
A wiring pattern formed on one surface of the base insulating layer;
A first insulating cover layer formed on the one surface of the insulating base layer so as to cover the wiring pattern;
The base insulating layer and the first cover insulating layer are bent so that at least a part of the wiring pattern faces each other,
A printed wiring board, wherein a spacer is disposed between the facing wiring pattern portions so that a distance between the facing wiring pattern portions is maintained at 0.5 mm or more. The printed wiring board according to claim 1, wherein the spacer has a relative dielectric constant of 1.1 or less. The printed wiring board according to claim 1, wherein the spacer is made of a porous material. The base insulating layer and the first cover insulating layer are bent inward from the first cover insulating layer,
The printed wiring board according to claim 1, wherein the spacer is disposed between the facing wiring pattern portions so as to be sandwiched between the first insulating cover layers. A ground layer formed on the other surface of the base insulating layer;
The printed wiring board according to claim 4, further comprising a second insulating cover layer formed on the other surface of the insulating base layer so as to cover the ground layer. The insulating base layer and the insulating first cover layer are bent inside the insulating base layer,
The printed wiring board according to claim 1, wherein the spacer is disposed between the facing wiring pattern portions so as to be sandwiched between the insulating base layers. Forming a wiring pattern on one surface of the base insulating layer;
Forming a first insulating cover layer on the one surface of the insulating base layer so as to cover the wiring pattern;
Bending the base insulating layer and the first cover insulating layer so that at least a part of the wiring patterns face each other;
And a step of arranging a spacer between the facing wiring pattern portions so that the distance between the facing wiring pattern portions is maintained at 0.5 mm or more. Production method.

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