CN-122002684-A - Printed wiring board

CN122002684ACN 122002684 ACN122002684 ACN 122002684ACN-122002684-A

Abstract

The invention provides a printed wiring board capable of improving transmission characteristics of high-frequency signals in a signal pattern. The printed wiring board includes a bending portion which is bendable in a bending direction in a plan view and has a first dielectric layer, a signal pattern, a second dielectric layer, a woven fabric, and a ground pattern. The first dielectric layer has a first major face. The signal pattern is disposed on the first main surface. The second dielectric layer has a second main surface and a third main surface, the second main surface being disposed so as to face the first main surface, and the third main surface being a surface facing the second main surface. The fabric is formed by weaving a plurality of first reinforcing fibers and a plurality of second reinforcing fibers into a cloth, wherein the plurality of first reinforcing fibers extend in a first direction in a plan view, and the plurality of second reinforcing fibers extend in a second direction inclined with respect to the first direction in a plan view.

Inventors

MORI KATSUYA
Xi Tuoren
Nishimura koucho

Assignees

住友电工印刷电路株式会社

Dates

Publication Date: 20260508
Application Date: 20251103
Priority Date: 20241106

Claims (9)

1. A printed wiring board includes a bending portion, The bending part can be bent along the bending direction in a plan view and is provided with a first dielectric layer, a signal pattern, a second dielectric layer, a first fabric and a grounding pattern, The first dielectric layer has a first major face, The signal pattern is arranged on the first main surface, The second dielectric layer has a second main surface and a third main surface, the second main surface being opposite to the first main surface, the third main surface being opposite to the second main surface, The first fabric is formed by weaving a plurality of first reinforcing fibers extending in a first direction in a plan view and a plurality of second reinforcing fibers extending in a second direction inclined with respect to the first direction in a plan view, The first fabric is disposed within the second dielectric layer, The ground pattern is disposed on the third main surface, The first direction and the second direction are each inclined with respect to the bending direction.
2. The printed wiring board according to claim 1, wherein, The first direction is perpendicular to the second direction.
3. The printed wiring board according to claim 2, wherein, The angle between the first direction and the bending direction is 30 DEG or more in a plan view.
4. The printed wiring board according to claim 2, wherein, The angle between the first direction and the bending direction is 40 DEG or more in a plan view.
5. The printed wiring board according to claim 1, wherein, The first plurality of reinforcing fibers and the second plurality of reinforcing fibers are formed from glass.
6. The printed wiring board according to claim 1, wherein, The second dielectric layer is formed of a fluororesin.
7. The printed wiring board according to claim 1, wherein, The printed wiring board further includes an adhesive layer disposed between the first main surface and the second main surface so as to cover the signal pattern.
8. The printed wiring board according to claim 1, wherein, The printed wiring board further includes a second fabric disposed in the first dielectric layer, The second fabric is formed by weaving a plurality of third reinforcing fibers extending in a third direction in a plan view and a plurality of fourth reinforcing fibers extending in a fourth direction inclined with respect to the third direction in a plan view, The third direction and the fourth direction are each inclined with respect to the bending direction.
9. The printed wiring board according to any one of claims 1 to 8, wherein, The bending portion is capable of bending in such a manner that the second dielectric layer is compressed.

Description

Printed wiring board Technical Field The present disclosure relates to printed wiring boards. Background Japanese patent application laid-open publication 2011-54919 (patent document 1) describes a printed wiring board. The printed wiring board described in patent document 1 has a first dielectric layer, a signal pattern disposed on the first dielectric layer, an adhesive layer disposed on the first dielectric layer so as to cover the signal pattern, a second dielectric layer disposed on the adhesive layer, and a ground pattern disposed on the second dielectric layer. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2011-54919 Disclosure of Invention Technical problem to be solved by the invention If the printed wiring board described in patent document 1 is bent so that the second dielectric layer is positioned further inside the bend than the first dielectric layer, compressive stress acts on the second dielectric layer. If the second dielectric layer is bent by the compressive stress, the distance between the signal pattern and the ground pattern, and thus the impedance of the signal pattern, changes, and the transmission characteristics of the high-frequency signal in the signal pattern become poor. The present disclosure provides a printed wiring board capable of improving transmission characteristics of high frequency signals in a signal pattern. Technical scheme for solving technical problems The printed wiring board of the present disclosure is provided with a bending portion. The bending portion is bendable in a bending direction in a plan view, and has a first dielectric layer, a signal pattern, a second dielectric layer, a woven fabric, and a ground pattern. The first dielectric layer has a first major face. The signal pattern is disposed on the first main surface. The second dielectric layer has a second main surface and a third main surface, the second main surface being disposed so as to face the first main surface, and the third main surface being a surface facing the second main surface. The fabric is formed by weaving a plurality of first reinforcing fibers and a plurality of second reinforcing fibers into a cloth, wherein the plurality of first reinforcing fibers extend in a first direction in a plan view, and the plurality of second reinforcing fibers extend in a second direction inclined with respect to the first direction in a plan view. The fabric is disposed within the second dielectric layer. The ground pattern is disposed on the third main surface. The first direction and the second direction are each inclined with respect to the bending direction. Effects of the invention According to the printed wiring board of the present disclosure, the transmission characteristics of the high-frequency signal in the signal pattern can be improved. Drawings Fig. 1 is a schematic side view of a printed wiring board 100. Fig. 2 is a plan view of the printed wiring board 100. Fig. 3 is a cross-sectional view at III-III in fig. 2. Fig. 4 is a schematic view showing the orientations of the reinforcing fibers 51a and the reinforcing fibers 51b in the woven fabric 51 disposed in the dielectric layer 50 in the bent portion 10 of the printed wiring board 100. Fig. 5 is a cross-sectional view of a printed wiring board 100 according to modification 1. Fig. 6 is a cross-sectional view of a printed wiring board 100 according to modification 2. Fig. 7 is a process diagram of manufacturing the printed wiring board 100. Fig. 8 is a first sectional view illustrating the production process S1. Fig. 9 is a second explanatory diagram illustrating the production process S1. Fig. 10 is a sectional view illustrating the patterning step S2. Fig. 11 is a schematic view showing the orientations of the reinforcing fibers 51a and the reinforcing fibers 51b in the woven fabric 51 disposed in the dielectric layer 50 in the bent portion 10 of the printed wiring board 200. Fig. 12 is a load-strain curve when the angle between the longitudinal direction of each sample and the first direction DR1 is changed. Fig. 13 is a graph showing the relationship between the angle formed by the longitudinal direction and the first direction DR1 and the fracture strain in each sample. Detailed Description [ Description of embodiments of the present disclosure ] First, embodiments of the present disclosure are listed for explanation. (1) The printed wiring board according to the embodiment includes a bending portion. The bending portion is bendable in a bending direction in a plan view, and has a first dielectric layer, a signal pattern, a second dielectric layer, a woven fabric, and a ground pattern. The first dielectric layer has a first major face. The signal pattern is disposed on the first main surface. The second dielectric layer has a second main surface and a third main surface, the second main surface being disposed so as to face the first main surface, and the third main surface bein