Vacuum Encapsulation of Electronic Components

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Solution Overview

Problem

Existing methods for encapsulating electrical and electronic components in a housing often result in air bubbles and incomplete insulation, leading to potential damage from outgassing electrolytic capacitors, especially when not fully encapsulated or surrounded by air bubbles.

Innovation Solution

Encapsulation is performed in a vacuum molding chamber at a pressure below atmospheric pressure, with negative pressure removal after encapsulation and before curing, and the use of flow pathways or channels to ensure complete coverage of the molding compound, along with temperature treatment for adhesion and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If encapsulation is performed at atmospheric pressure, then the process is simple and fast, but air bubbles form in the molding compound and components are not fully insulated

Engineering Contradiction:
Improveencapsulation qualityVSAvoidencapsulation process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies vacuum environment (inert atmosphere principle) by performing encapsulation in a vacuum chamber. The vacuum removes air from the chamber before injecting molding compound, preventing air bubbles from forming in the encapsulated components. This resolves the contradiction by maintaining high encapsulation quality without requiring overly complex equipment, as standard vacuum chambers are used in manufacturing.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent applies preliminary action by evacuating the vacuum chamber and removing air before injecting the molding compound. This preliminary removal of air prevents bubble formation during encapsulation, ensuring complete insulation of components while keeping the process straightforward and sequential.

Inventive Principle:
Principle #10Preliminary action

2Volume of moving object

If components are placed close together for miniaturization, then assembly size is reduced, but electrical insulation between components becomes insufficient

Engineering Contradiction:
Improveassembly sizeVSAvoidelectrical insulation
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

By using vacuum encapsulation, the molding compound fully penetrates between closely spaced components without air bubbles, providing complete electrical insulation. This allows components to be placed as close as possible for miniaturization while maintaining reliable insulation through the bubble-free molding compound.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Reliability

If electrolytic capacitors are not fully encapsulated or surrounded by air bubbles, then outgassing can occur during operation, but complete encapsulation requires complex processing

Engineering Contradiction:
Improveassembly reliabilityVSAvoidencapsulation ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Vacuum encapsulation ensures molding compound completely fills all spaces around electrolytic capacitors without air bubbles. This full encapsulation prevents outgassing during operation while using a relatively simple process of vacuum chamber evacuation followed by compound injection, maintaining ease of manufacture.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 method prevents air bubble formation, ensures complete insulation, and allows for closer component placement, enhancing miniaturization and reliability of electronic assemblies by ensuring all components are fully encapsulated and sealed.

Implementation Method 1

the encapsulating preferably takes place in a molding chamber at a pressure below atmospheric pressure and the negative pressure is removed after encapsulation and before curing

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentUS8821778B2Method for encapsulating electrical and/or electronic components in a housing
Publication Date: 2014.09.02 KRAUS HILMAR

AI summary

The invention relates to a method for encapsulating electrical and/or electronic components in a housing, the components being arranged on a printed circuit or a strip conductor in an assembly. Said assembly is positioned in the housing and is encapsulated with a curing, electrically insulating molding compound. The method according to the invention is characterized by encapsulating preferably in a molding chamber at a pressure below atmospheric pressure and by removing the negative pressure after encapsulation and before curing.