Printed Wiring Board with Region-Specific Lamination for Bending Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Printed wiring boards face challenges in achieving both reduced thickness and improved bending resistance, particularly due to the insufficient bending resistance when the thickness of conductive patterns in terminal parts is made thin, and the complexity of maintaining structural strength with varying laminated structures.
Innovation Solution
A printed wiring board design incorporating an insulating base material, first and second conductive layers, and an insulating layer, where the ratio of evaluation values for strength in different regions is optimized by adjusting the thickness of these layers, and the insulating layer's end part is configured non-linearly to distribute stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of conductive patterns in the terminal part is made thin, then the overall thickness is reduced, but the bending resistance becomes insufficient
Solution Approach 1:
The patent applies different laminated structures to different regions: the terminal part uses a thinner structure (first conductive layer only) while the wiring part uses a thicker structure (first conductive layer + insulating layer). This local differentiation allows the terminal part to achieve reduced thickness for flexibility while the wiring part maintains sufficient bending resistance through increased thickness.
Solution Approach 2:
The conductive pattern is segmented into two distinct regions with different thickness characteristics. The terminal part (first region) has a thinner laminated structure while the wiring part (second region) has a thicker laminated structure. This segmentation enables each region to be optimized independently for its specific functional requirements.
2Adaptability or versatility
If the thickness of conductive patterns is reduced, then the board becomes more flexible, but the structural strength decreases
Solution Approach 1:
Different regions of the board have different thickness properties: the terminal part is thinner for flexibility and adaptability, while the wiring part is thicker for structural strength. This local quality differentiation resolves the contradiction by allowing flexibility where needed and strength where required.
Solution Approach 2:
The patent introduces a dimensional variation in the thickness direction (z-axis) by creating a stepped structure where the insulating layer is present in the wiring part but absent in the terminal part. This dimensional change enables simultaneous achievement of flexibility and structural strength in different areas of the same board.
3Reliability
If different laminated structures are used in different regions, then regional performance is optimized, but the manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct steps for forming the terminal part and wiring part with different laminated structures. The insulating layer is selectively formed only in the wiring part region, creating a clear manufacturing sequence that, while multi-step, is systematically organized and manageable.
Data Source
AI summary
A printed wiring board includes: an insulating base material; a first conductive layer disposed on a main surface of the insulating base material in a first region and a second region defined on a plane along the main surface; a second conductive layer disposed on a main surface of the first conductive layer in the first region; and an insulating layer disposed on the main surface of the first conductive layer in the second region. The ratio of a first evaluation value E1 to a second evaluation value E2 is 0.91 or more and 0.99 or less. The first evaluation value E1 is an evaluation value of strength of a first laminated part in the first region and the second evaluation value E2 is an evaluation value of strength of a second laminated part in the second region.