Flexure Wiring Structure With Interleaved Sub-Trace Width Variation
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Solution Overview
Problem
The interleaved wiring technique in hard disk drives causes partial dips in the frequency characteristic of signal transmission loss, leading to unwanted filtering and reduced bandwidth, which are not present in standard wiring configurations.
Innovation Solution
A wiring structure for a flexure with interleaved sections where the sub-traces of each polarity are alternated in width, with the outer sub-traces being narrower than the inner sub-traces, connected on each side of the interleaved section, to prevent partial dips in the frequency characteristic of signal transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interleaved wiring technique is used to reduce impedance and inductance, then electric characteristics are improved, but partial dips occur in the frequency characteristic of signal transmission loss
Solution Approach 1:
The patent applies local quality by making the outer sub-traces narrower than the inner sub-traces at the interleaved section. This creates a localized geometric variation that specifically addresses the harmful partial dips in frequency response while preserving the overall benefits of interleaved wiring for impedance reduction. The non-uniform width distribution is concentrated at the problematic interleaved regions only.
2Reliability
If interleaved wiring technique is used to reduce impedance, then impedance matching with preamplifier is achieved, but bandwidth is narrowed due to unwanted filtering
Solution Approach 1:
The patent changes the geometric parameter of sub-trace widths by making outer sub-traces narrower than inner sub-traces. This parameter modification adjusts the electromagnetic characteristics locally to eliminate unwanted filtering effects while maintaining the impedance matching benefits of the interleaved configuration, thereby preserving bandwidth.
3Object-generated harmful factors
If standard wiring configuration is used, then no partial dips occur in frequency characteristic, but impedance and inductance are higher
Solution Approach 1:
The patent segments the wiring into sub-traces with different width characteristics at the interleaved section. By dividing the trace structure and applying different width parameters to different segments (outer vs inner sub-traces), the invention achieves both impedance reduction and eliminates frequency dips, combining the advantages of both standard and interleaved wiring approaches.
Data Source
AI summary
A wiring structure of a flexure includes wiring that includes a trace of first polarity and a trace of second polarity and transmits signals to and from a head that is supported with the flexure and writes and reads data to and from a recording medium and an interleaved section formed at least partly in the wiring where the traces are each divided into sub-traces, the sub-traces being alternated in a width direction of the wiring, the sub-traces of each trace being connected to each other on each side of the interleaved section, an outer one of the sub-traces of each trace being narrower than an inner one of the same. The wiring structure reduces partial dips in the frequency characteristic of signal transmission loss (loss-to-frequency characteristic) of the wiring at the interleaved section.