Optical Module Flexible Substrate Pad Thickness
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Solution Overview
Problem
The instability in electrical conduction between Flexible Printed Circuits (FPC) units and connectors in optical modulators due to varying pad thicknesses and structures on different surfaces, leading to potential contact failures and unreliable connections.
Innovation Solution
The optical module employs a flexible substrate with conductor patterns on both surfaces connected via through holes, ensuring uniform pad configuration and thickness, stabilizing electrical conduction by maintaining consistent contact with terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiring patterns are formed on both front and rear surfaces of the FPC unit to connect lands and pads, then the electrical connection between connector terminals and modulator lead pins is achieved, but the pad thickness varies depending on the surface, causing unstable electrical conduction
Solution Approach 1:
The patent applies local quality by making pads connected to rear-surface wiring patterns thicker than those connected to front-surface wiring patterns. This localized differentiation compensates for the additional via hole depth required for rear-surface connections, ensuring uniform electrical conduction stability across all pads despite their different construction methods.
Solution Approach 2:
The patent implements preliminary action by pre-adjusting the thickness of pads connected to rear-surface wiring patterns during the manufacturing process. This advance compensation ensures that all pads achieve uniform electrical conduction characteristics before the FPC unit is assembled and deployed, preventing conduction instability issues.
2Device complexity
If all pads are formed on a single surface of the FPC unit to contact terminals on a single plane, then the connector connection is simplified, but wiring patterns on the same surface must not intersect, increasing device complexity
Solution Approach 1:
The patent applies dimensionality change by utilizing both the front and rear surfaces of the FPC unit for forming wiring patterns and pads. This transitions from a single-surface (2D) layout to a dual-surface (3D) configuration, allowing wiring patterns to be distributed across different surfaces and avoiding intersections while maintaining manufacturing feasibility.
3Reliability
If pads connected to rear-surface wiring patterns are made thicker to compensate for via hole depth, then electrical conduction stability is improved, but the pad thickness becomes non-uniform across the FPC unit
Solution Approach 1:
The patent applies local quality by making pads connected to rear-surface wiring patterns thicker than those connected to front-surface wiring patterns. This localized differentiation compensates for the additional via hole depth required for rear-surface connections, ensuring uniform electrical conduction stability across all pads despite their different construction methods.
Data Source
AI summary
An optical module includes: an optical modulator that performs an optical modulation process by using electrical signals input from a plurality of terminals; and a flexible substrate that has flexibility and electrically connects the optical modulator and a predetermined connector to each other via a plurality of wiring patterns formed on first and second surfaces thereof. The flexible substrate includes: a first pad including a first conductor pattern connected, on the first surface, to a wiring pattern, a second conductor pattern formed on the second surface, and a through hole that connects the first conductor pattern and the second conductor pattern to each other; and a second pad including a third conductor pattern connected, on the second surface, to a wiring pattern, a fourth conductor pattern formed on the first surface, and a through hole that connects the third conductor pattern and the fourth conductor pattern to each other.