Hearing Aid Circuit Coating via Component Masking

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Solution Overview

Problem

The production of hearing aid circuits faces challenges in reducing costs and minimizing errors due to the complexity of protecting conductor tracks and components from corrosive environments, particularly human perspiration and cerumen, while maintaining a compact size and avoiding damage during coating removal processes.

Innovation Solution

A method involving a printed circuit board with distinct areas separated by a border, where components are attached to cover the border, allowing for selective masking and coating application, followed by separation of the coating along the component's edge to prevent damage and ensure complete coverage of the exposed areas, using inexpensive tools and techniques like blades or lasers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mask is used to protect areas during coating application, then complete and precise coating coverage is achieved, but the complexity of the production process increases due to additional masking and removal steps

Engineering Contradiction:
Improvecoating coverage precisionVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The conductor tracks are pre-coated with the protective coating material before the electronic components are mounted on the circuit board. This preliminary coating action eliminates the need for subsequent masking steps, as the coating is already in place before components are attached, thereby maintaining precision while reducing process complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of the conventional approach of mounting components first and then applying coating (which requires masking to protect components), the patent inverts the sequence by applying the coating to the conductor tracks first, then mounting the components. This reversal eliminates the masking step entirely while ensuring complete coating coverage

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If expensive specialized tools are used for coating separation, then damage to the printed circuit board is minimized, but the production costs increase

Engineering Contradiction:
Improvecircuit board integrityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The protective coating is preliminarily applied to the conductor tracks before component mounting, creating a robust protective layer that prevents the need for costly separation tools. The coating itself serves as the protective barrier, eliminating the need for additional expensive tools to protect the circuit board during subsequent processes

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs inexpensive, easily removable masking materials that can be discarded after use, replacing expensive specialized separation tools. The masking tape or similar low-cost materials are applied temporarily during coating application and then removed without causing damage, providing an economical alternative to costly specialized equipment

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Volume of moving object

If the circuit is made compact for hearing aid application, then the overall size is reduced, but the susceptibility to damage from corrosive environments increases

Engineering Contradiction:
Improvecircuit sizeVSAvoidcorrosion susceptibility
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A thin film protective coating is applied over the conductor tracks and electronic components, providing a flexible yet effective barrier against corrosive environments such as perspiration and cerumen. This thin film protection maintains the compact size of the hearing aid circuit while preventing corrosion, as the coating layer is sufficiently thin to not significantly increase overall dimensions

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The circuit board employs a composite structure combining the conductive traces, electronic components, and a protective coating layer, creating a multi-material assembly that is both compact and corrosion-resistant. The composite nature of the circuit board integrates protection directly into the structure, maintaining small size while enhancing durability against harmful environmental factors

Inventive Principle:
Principle #40Composite materials

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 reduces production costs and errors by ensuring complete and precise coating of the circuit, preventing damage to the printed circuit board, and allowing for the use of inexpensive tools, while maintaining the circuit's functionality and robustness against corrosive environments.

Implementation Method 1

the coating is provided with the circuit board except for the areas covered by the mask. After the coating has cured, the mask is removed from the circuit board

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

the coating around the mask must first be separated, which is usually done using a laser or comparatively sharp-edged and precisely manufactured tools

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3275295B1Method for manufacturing a circuit of a hearing aid
Publication Date: 2023.01.18 SIVANTOS PTE LTD
  • EP3275295B1 patent drawingFigure 1~2
  • EP3275295B1 patent drawingFigure 3~6

AI summary

The invention relates to a method (2) for manufacturing a circuit (4), in particular of a hearing aid (6), in which method (2) a printed circuit board (10) is made available with a first region (14) and with a second region (12) which are separated by means of a boundary (18). A component (24) is mounted on the printed circuit board (10), wherein the component (24) is positioned on the boundary (18). The first region (14) is covered by means of a mask (38) which has an edge (42), wherein the edge (42) is positioned on the component (24), and the printed circuit board (10) is provided with a coating (46). The coating (46) is cut away in the region of the component (24) and the mask (38) is removed.