Parylene Coated Circuit Board for Electric Drive Protection
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Solution Overview
Problem
Existing methods for protecting circuit boards from moisture and chemical environmental effects, such as parylene coating, require additional machining steps that increase manufacturing costs and risks, and can lead to unprotected areas and dendrite formation causing short-circuits.
Innovation Solution
A thin parylene coating is applied to the circuit board, covering all areas except where press-fit contacts are inserted, ensuring direct electrical contact without adverse mechanical effects, and allowing narrower component spacings to prevent dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circuit board is fully coated with parylene for protection, then protection against moisture and chemicals is improved, but additional machining steps are required to create contact areas
Solution Approach 1:
The parylene coating is applied to the entire circuit board before the contact areas are defined. The coating process is performed in advance, and the contact areas are subsequently created by removing the coating only where needed, rather than trying to apply the coating selectively from the beginning.
Solution Approach 2:
The contact areas are created by removing (extracting) the parylene coating from specific regions of the circuit board. This allows the majority of the board to remain fully protected while exposing only the necessary contact areas for electrical connections.
2Reliability
If masking material is applied before CVD process to protect contact areas, then electrical connection is maintained, but manufacturing costs and risks increase
Solution Approach 1:
Instead of applying masking material to protect contact areas during the coating process, the approach is inverted: the entire board is coated first, and then the masking material is used to define and expose the contact areas by selective removal. This reverses the traditional sequence of protection and exposure.
3Reliability
If parylene coating is applied to the circuit board, then protection is improved, but contact openings require additional processing
Solution Approach 1:
The parylene coating is applied to the circuit board in advance, before the contact openings are processed. This preliminary coating step ensures complete protection of the board, and the contact openings are subsequently created by selective removal of the coating, simplifying the overall process sequence.
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 solution provides reliable protection against moisture and chemicals while maintaining mechanical integrity and preventing short-circuits by ensuring only contact areas are exposed, reducing manufacturing complexity and costs.
Implementation Method 1
The protective coating is applied to the substrate as a pore-free and transparent polymer film in vacuum by condensation from a gas phase (CVD process/chemical vapor deposition)
Implementation Method 2
In the electrical contact areas (9) within the contact openings (4), electrical contact exists between the press-fit contact (8) and the plated through-hole (5) of the contact opening (4)
Data Source
AI summary
An electric drive (1) with a circuit board (2), having conductor tracks (3) and contact openings (4) with plated through-holes (5) and equipped with electronic components (6), the circuit board (2) being coated with a protective layer (7) of insulating material, and press-fit contacts (8) are inserted into the contact openings (4) and in electrical contact areas (9) within the contact openings (4) electrical contact exists between a press-fit contact (8) and the plated through-hole (5) of the contact opening (4). The task of the invention is to reliably protect circuit boards of electric drives exposed to moisture and other chemical environmental effects and contact them economically. This task is solved according to the invention in that the protective layer (7) is a parylene coating, which covers the circuit board (2), the electronic components (6) and the surface areas of the contact openings (4) and circuit board (2) directly connected to the contact areas (9) between at least one press-fit contact (8) and at least one contact opening (4).