Printed Wiring Board Thick Insulating Layer Signal Uniformity
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Solution Overview
Problem
Existing printed wiring boards face issues with signal transmission rate differences due to variations in dielectric constants between warp and weft threads and resin, leading to reduced signal amplitude and increased data transmission rate, which are not adequately addressed by existing methods such as opening treatments or oblique signal line arrangements.
Innovation Solution
A printed wiring board design featuring a laminated structure with a thick and thin insulating layer configuration, where the signal layer is positioned far from the substrate, reducing the impact of high dielectric constant substrates and ensuring uniform signal transmission by using resin with a low dielectric constant, eliminating the need for oblique signal line arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If signal lines are arranged parallel to warp or weft threads to increase wiring density, then wiring density is improved, but signal transmission rate difference increases due to dielectric constant variations
Solution Approach 1:
The patent changes the physical parameter of signal line orientation from parallel to oblique relative to the warp and weft threads. Specifically, signal lines are arranged at angles of 15-45 degrees or 135-165 degrees relative to the warp threads, which reduces the impact of dielectric constant variations caused by thread orientation and achieves more uniform signal transmission rates while maintaining high wiring density
2Reliability
If opening treatment is applied to reduce gaps between threads, then dielectric constant uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of modifying the substrate structure through opening treatment to achieve uniformity, the patent inverts the approach by modifying the signal line arrangement to avoid the non-uniform regions. By orienting signal lines obliquely, the design works around the dielectric variations rather than attempting to eliminate them, thereby achieving uniform signal transmission without additional manufacturing complexity
3Reliability
If oblique signal line arrangement is used to reduce transmission rate difference, then signal transmission uniformity is improved, but wiring density decreases
Solution Approach 1:
The patent optimizes the oblique angle parameters to achieve a balance where signal lines are oriented at 15-45 degrees or 135-165 degrees relative to warp threads. This specific angular range allows the signal lines to effectively cross multiple thread directions, averaging out dielectric constant variations and achieving uniform signal transmission while still maintaining high wiring density through efficient space utilization
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly reduces the difference in signal transmission rates and suppresses signal divergence, allowing for higher wiring density and efficiency in producing multiple printed wiring boards from a single substrate without the need for oblique signal lines.
Implementation Method 1
a portion including the warp threads 110 of glass fibers and the weft threads 120 of glass fibers has a high dielectric constant. In contrast, a portion between the warp threads 110 and 110 and/or between the weft threads 120 and 120 dominantly includes the resin 140 and thus has a low dielectric constant
Data Source
AI summary
An object of the present invention is to provide a printed wiring board which does not require arranging signal lines oblique to the warp or weft threads constituting a substrate and is capable of reducing a difference in transmission rates between the signal lines. The present invention relates to a printed wiring board including: an insulating layer; and a signal layer including a set of at least two signal lines and disposed on one side of the insulating layer. A substrate is embedded inside the insulating layer in such a manner to be further from the signal layer than a center of the insulating layer in a thickness direction of the insulating layer is. The insulating layer has a laminated structure of a thick layer, the substrate, and a thin layer. A ratio of a thickness of the thick layer to a thickness of the thin layer is greater than five.