Suspension Substrate Bifurcated Wiring Impedance Reduction
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Solution Overview
Problem
Existing suspension substrates for hard disk drives face challenges in enhancing electric properties while maintaining manufacturing simplicity, as they often require complex structures and increased costs to reduce impedance and noise, such as multilayered wiring configurations and shield layers.
Innovation Solution
A suspension substrate design featuring a spring material layer with bifurcated wiring parts connected via conductive connecting parts through the insulating layer, allowing for alternate arrangement of division wiring parts to reduce impedance and noise, while simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the space between differential wirings is narrowed to reduce impedance, then the impedance is reduced, but the risk of short circuit increases
Solution Approach 1:
The patent introduces a ground wiring as an intermediary element positioned between the differential wirings. This ground wiring acts as a shield that electrically connects to ground potential, thereby reducing the impedance of the differential signal path while preventing direct short circuits between the positive and negative differential lines. The ground wiring mediates the electromagnetic field interaction and provides a reference potential that stabilizes the signal transmission.
2Object-affected harmful factors
If multilayered wiring structures are used to reduce noise, then the noise reduction is achieved, but the manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functional elements into a single planar layer. Instead of using separate shield layers and complex multilayered structures, the ground wiring is integrated directly into the same insulating layer as the differential wirings, forming a coplanar configuration. This merging approach achieves noise reduction through proper grounding while maintaining a simple two-layer structure (conductive layer + insulating layer), thereby avoiding the manufacturing complexity of multilayered PCBs or coaxial cables.
3Object-affected harmful factors
If shield layers are added to conductive members to reduce noise, then the noise reduction is achieved, but the manufacturing process becomes complicated
Solution Approach 1:
The patent uses a thin film approach where the ground wiring is formed as a conductive pattern on the insulating layer, creating a planar shield rather than a bulky three-dimensional shield structure. This thin film configuration provides effective electromagnetic shielding and noise reduction while being compatible with standard PCB fabrication processes, avoiding the need for complex assembly operations or specialized shielding components.
Data Source
AI summary
A suspension substrate according to the present invention includes: an insulating layer; a spring material layer provided on one face of the insulating layer and having conductivity; and a plurality of wirings provided on the other face of the insulating layer. One wiring includes a head-side wiring part extending from the head portion, and a plurality of division wiring parts respectively bifurcated from the head-side wiring part. The spring material layer includes a spring material main body, and a wiring spring material part separated from the spring material main body, via a groove. A conductive connecting part extending through the insulating layer is provided in the insulating layer. Each of the division wiring parts of the one wiring is connected with the wiring spring material part, via the conductive connecting part.