Multi-layered Silicone Coating for Water-Resistant PCBs

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Solution Overview

Problem

Conventional methods for manufacturing water-resistant printed circuit boards (PCBs) used in automotive EPS systems with ADAS are inadequate, as they only provide temporary protection against water, require extensive space, and have long application times, making them unsuitable for continuous underwater operation.

Innovation Solution

A method involving a multi-layered silicone water-resistant coating applied using standard coating systems, which includes cleaning and plasma treatment of the PCBs to enhance surface energy and facilitate uniform coating, allowing for streamlined production and improved thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional vapor deposition methods using Parylene C or F are used to provide water resistance, then water-resistant coating is achieved, but application time becomes excessively long (12-18 hours)

Engineering Contradiction:

Improvewater resistanceVSAvoidapplication time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the material parameter from Parylene C/F to silicone-based coating, and changes the application method parameter from vapor deposition to conventional coating techniques, thereby reducing application time from 12-18 hours to a much shorter duration while maintaining water resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the complex vapor deposition mechanical system with a simpler conventional coating system, substituting the lengthy thermal vaporization and deposition process with a more efficient coating application method that achieves the same protective function in less time

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If dam features are used to contain silicone gel coating, then water resistance is achieved, but space requirements increase and dual board systems cannot be accommodated

Engineering Contradiction:

Improvewater resistanceVSAvoidspace requirement

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts and removes the dam feature from the coating system, eliminating the need for physical containment structures while maintaining effective water resistance through the silicone gel coating's inherent properties, thereby freeing up space and enabling dual board configurations

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a homogeneous silicone gel coating that uniformly covers the circuit board surface without requiring physical barriers, allowing the coating to flow and conform to the board geometry naturally, which enables application to complex multi-board assemblies without additional structural constraints

Inventive Principle:

Principle #33Homogeneity

3Reliability

If conventional coating methods are used, then water resistance is provided, but manufacturing cost increases and process streamlining becomes difficult

Engineering Contradiction:

Improvewater resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a silicone-based coating system that uses readily available, cost-effective materials and standard coating equipment rather than expensive specialized vapor deposition systems, reducing manufacturing cost while achieving the required water resistance for the application lifecycle

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a universal coating process that can be applied to various circuit board configurations and sizes using standard equipment, making the manufacturing process more flexible and cost-effective compared to specialized vapor deposition systems that require custom racks and extended processing times

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

The method provides a cost-effective, space-efficient, and durable water-resistant coating that can withstand a wide range of operational temperatures and maintain functionality indefinitely under water, with reduced manufacturing costs and streamlined processes.

Implementation Method 1

cleaning and plasma treatment of the PCBs to enhance surface energy and facilitate uniform coating

Methodology Applied

Scientific EffectPlasma treatment: Plasma

Implementation Method 2

depositing a multi-layered water resistant coating onto the cleaned substrate. The multi-layered water resistant contains silicone

Methodology Applied

Scientific EffectHydrophobic barrier: Hydrophobe

Data Source

PatentUS11439024B2Method for manufacturing water resistant printed circuit board

Publication Date: 2022.09.06 STEERING SOLUTIONS IP HOLDING CORP

AI summary

A method for manufacturing a water resistant substrate comprises a first step of providing a substrate. The method proceeds with a step of populating at least one component onto the substrate. Next, the method includes a step of cleaning the substrate including the at least one component to form a cleaned substrate. Then, the method proceeds with depositing a multi-layered water resistant coating onto the cleaned substrate.