Low Permeability Electrical Feed-Through Laminate Structure
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Solution Overview
Problem
Hermetically sealed hard disk drives face challenges in achieving a low leakage rate while maintaining cost-effectiveness for electrical feed-throughs, as existing solutions like glass-metal feed-throughs are expensive and PCB feed-throughs have higher leak rates.
Innovation Solution
A low permeability electrical feed-through is developed using a laminate structure with conductive and insulator layers, including a glass-epoxy resin and copper-clad laminate, which biases gas leakage in the horizontal direction and incorporates a conductive annulus to inhibit gas diffusion, while minimizing capacitance effects on high-frequency signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass-metal feed-through is used, then gas leakage is reduced, but cost increases
Solution Approach 1:
The patent employs a composite structure combining glass-epoxy resin layers with copper-clad laminate layers. The glass-epoxy resin provides hermetic sealing properties to reduce gas leakage, while the copper-clad laminate provides electrical conductivity. This composite approach achieves the low leakage performance of glass-metal feed-throughs while avoiding their high cost by using standard PCB materials and manufacturing processes.
2Ease of manufacture
If PCB feed-through is used, then cost is reduced, but gas leakage increases
Solution Approach 1:
The patent uses a composite laminate structure with alternating layers of glass-epoxy resin and copper-clad laminate. The glass-epoxy resin layers provide the hermetic sealing necessary to prevent gas leakage, while the copper-clad layers provide electrical pathways. This maintains the cost-effectiveness of PCB manufacturing while achieving the required hermetic performance.
Solution Approach 2:
The patent implements localized hermetic sealing by placing glass-epoxy resin layers specifically at regions where gas leakage would occur, rather than making the entire structure hermetic. The conductive annulus is positioned at the interface between the feed-through and the sealed enclosure to provide targeted leakage prevention. This allows standard PCB materials to be used while achieving low leakage rates at critical locations.
3Reliability
If conductive annulus is added to inhibit gas diffusion, then gas leakage is reduced, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into the conductive annulus: it provides electrical connectivity between signal traces, acts as a barrier to gas diffusion through the hermetic seal, and serves as a structural element of the laminate. By merging these functions into a single integrated feature, the patent reduces overall device complexity compared to having separate components for each function.
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
The solution provides a cost-effective electrical feed-through with reduced gas leakage, maintaining structural integrity and minimizing the impact on high-frequency signal transmission.
Implementation Method 1
A low permeability electrical feed-through includes a laminate structure having a first layer of conductive material, or first conductor layer, over a first side of a copper clad laminate first insulator material and a second layer of conductive material, or second conductor layer, over a second opposing layer side of the first insulator layer
Implementation Method 2
incorporates a conductive annulus to inhibit gas diffusion
Data Source
AI summary
A low permeability electrical feed-through involves a laminate structure having alternating conductive and insulating layers with a conductive through-hole positioned therethrough, by which a lower connector pad is electrically connected with an upper connector pad. Such a feed-through may be used at an interface between a hermetically-sealed internal environment, such as in a lighter-than-air gas filled data storage device, and the external environment. An insulating layer is positioned and configured such that an associated horizontal leak path can meet an allowable feed-through leak rate, while the collection of layers is configured such that an associated vertical leak path can meet the feed-through leak rate.