Optical Module Electrical Isolation via Insulating Bush

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Solution Overview

Problem

Existing optical modules have complex structures for electrical isolation of semiconductor devices from optical receptacles, leading to increased costs and potential reliability issues due to compressive stress and press-fitting requirements.

Innovation Solution

A simplified optical module design featuring a sleeve, stub, holder, bush, and shell, where the bush is press-fitted with the holder and shell, balancing expanding and compressive stresses to securely isolate the holder from the shell, using materials like ceramics and stainless steel with matching thermal expansion coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating spacer is set between stub holder and sleeve cover to electrically isolate metal components, then electrical isolation is achieved, but structure becomes complex and reliability decreases due to compressive stress

Engineering Contradiction:

Improveelectrical isolation reliabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the electrical isolation function from the complex multi-component assembly (insulating spacer between stub holder and sleeve cover) and concentrates it into a single integrated insulating sleeve that surrounds the optical device and connects to the shell. This simplification eliminates the compressive stress issue while maintaining electrical isolation reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The insulating sleeve combines multiple functions into one component: it provides electrical isolation between the metal stub holder and shell, mechanical support for the optical device, and structural connection to the shell. This merging eliminates the need for separate insulating spacers and reduces overall structural complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If insulating ring is press-fitted between metal rings to isolate optical device, then electrical isolation is achieved, but manufacturing complexity increases and insulating ring must be formed in thin

Engineering Contradiction:

Improveelectrical isolationVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the electrical isolation function into a dedicated insulating sleeve component that is separately manufactured and then assembled into position between the metal stub holder and shell. This segmentation allows each component to be optimized independently, avoiding the need for complex press-fitting operations and thin-walled insulating rings.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insulating sleeve acts as an intermediary component that provides a stable, reliable electrical isolation barrier between the metal stub holder and shell. Unlike press-fitted insulating rings that require precision and have limited thickness options, the insulating sleeve can be manufactured with optimal wall thickness and assembled into position, significantly improving manufacturing ease.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If complex insulating structures are used to shield optical device from EMI and surge, then protection is improved, but cost increases

Engineering Contradiction:

ImproveEMI and surge protectionVSAvoidstructure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The insulating sleeve serves multiple functions simultaneously: it provides electrical isolation between metal components, acts as a shield against EMI and external surge, provides mechanical support for the optical device, and establishes structural connection to the shell. This multi-functionality eliminates the need for separate protective structures, reducing overall complexity and cost while maintaining comprehensive protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides effective electrical isolation, reduces external noise interference, and enhances reliability while being cost-effective by simplifying the assembly process and minimizing stress-related structural complexities.

Implementation Method 1

the bush receives an expanding stress from the holder, while, the bush receives a compressive stress from the shell, which reliably holds the bush between the holder and the shell

Methodology Applied

Scientific EffectStress balancing:

Implementation Method 2

a bush made of electrically insulating material and receiving the holder therein; and a shell that covers the sleeve, the stub, the holder and the bush, being made of electrically conductive material. The bush of the invention electrically isolates the holder from the shell

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS8083419B2Optical module with an optical device electrically isolated from a sleeve shell

Publication Date: 2011.12.27 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

An optical module has disclosed, in which the optical module electrically isolates the optical device from the sleeve shell with a simple and a cost-effective arrangement. The optical receptacle includes the metal holder to hold the stub, the insulating bush to press-fit the holder, and the metal shell to press-fit the bush. The bush electrically isolates the holder from the shell, and has a length press-fitted to the shell overlapping with a length press-fitted to the holder.