Optical Modulator FPC Vibration Resilience Design

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Solution Overview

Problem

Optical modulators with flexible printed circuits (FPCs) face issues with peeling-off or cracks due to environmental vibrations during transportation and operation, leading to deterioration of radio-frequency characteristics and optical modulation performance.

Innovation Solution

The optical modulator incorporates a flexible printed circuit with a quadrilateral shape, featuring additional fixing portions and notched portions to increase the natural vibration frequency, which are connected to additional lead pins and the circuit substrate, thereby reducing the impact of environmental vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If lead pins and FPC are used instead of coaxial connectors for RF electrode connection, then housing size is reduced and mounting space is minimized, but the FPC becomes susceptible to peeling-off and cracks due to environmental vibrations

Engineering Contradiction:

Improvehousing sizeVSAvoidFPC connection stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies vibration isolation techniques by introducing damping materials and flexible mounting structures between the FPC and housing to reduce the transmission of environmental vibrations, thereby preventing peeling-off and cracks while maintaining the compact design

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent incorporates protective measures in advance by adding vibration-damping elements and reinforcement structures to the FPC assembly before exposure to environmental vibrations, ensuring connection stability without increasing overall size significantly

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If multiple push-on type coaxial connectors are provided for RF electrodes in DP-QPSK optical modulator, then reliable RF connection is achieved, but housing size increases significantly

Engineering Contradiction:

ImproveRF connection reliabilityVSAvoidhousing size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical push-on coaxial connector system with an electrical connection system using lead pins and FPC, eliminating the need for large mechanical interfaces while maintaining RF signal transmission functionality through soldered or pressed connections

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If FPC is used to connect lead pins to circuit substrate, then coaxial cable excess-length processing is eliminated and mounting space is reduced, but vibration-induced peeling-off and cracks occur at connection points

Engineering Contradiction:

Improvemounting spaceVSAvoidvibration impact

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces intermediary elements such as damping materials, flexible buffers, and reinforcement structures between the FPC and connection points (lead pins and circuit substrate) to mediate the vibration forces, preventing direct transmission that causes peeling-off and cracks

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration effectively suppresses peeling-off and cracks, maintaining stable radio-frequency characteristics and optical modulation performance by shifting the natural vibration frequency beyond the environmental vibration range.

Implementation Method 1

additional fixing portions and notched portions which are configured to increase a natural vibration frequency of the flexible printed circuit

Methodology Applied

Scientific EffectVibration: Vibration

Data Source

PatentUS10595398B2Optical modulator with FPC, and optical transmission apparatus using same

Publication Date: 2020.03.17 SUMITOMO OSAKA CEMENT CO LTD

AI summary

To suppress peeling-off or cracks of a solder-fixing portion, which are caused by vibration during transportation or operation, in an optical modulator with FPC, thereby suppressing deterioration of radio-frequency characteristics of a signal path in an effective manner at low cost.An optical modulator 100 includes a flexible printed circuit (106) that performs electrical connection with a circuit substrate. The flexible printed circuit has a substantially quadrilateral shape. In the flexible printed circuit, a pad (210 and the like), which is electrically connected to the circuit substrate, is provided along one side of the substantial quadrilateral. In addition, in the flexible printed circuit, signal patterns (220 and the like), which are connected to signal lead pins (120 and the like) for signal transmission which is provided in the optical modulator, are provided in another side opposite to the one side. In addition, the flexible printed circuit includes an additional fixing portion (240 and the like) and/or a notched portion (810 and the like) which are configured to increase a natural vibration frequency of the flexible printed circuit in a state of being connected to the signal lead pin and the circuit substrate.