Amorphous Fluorinated Polymer Coating for RF Circuit Boards
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
RF circuit board assemblies lack protective conformal coatings, leading to potential short-circuits and corrosion due to exposure, and existing coating methods like vapor phase processes are impractical for larger boards as they cannot cover solder balls and result in thicker, less precise coatings.
Innovation Solution
A method using a mechanically controlled fluid spray application of an amorphous fluorinated polymer dissolved in a fluorinated solvent, such as Teflon™ AF in Vertrel™ XF, to apply a thin, conformal coating to RF circuit boards, which evaporates, leaving behind a protective layer that adheres without degrading RF performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If vapor phase coating process is used, then coating can be applied to small circuit boards, but the coating chamber size is limited and cannot accommodate larger RF circuit boards
Solution Approach 1:
The patent replaces the vapor phase deposition process with a liquid spray coating process. The coating solution is applied as a liquid spray that can cover large areas, and the solvent evaporates to leave the polymer coating. This substitution of the deposition mechanism enables accommodation of large RF circuit boards while maintaining thin coating control.
Solution Approach 2:
The patent changes the physical state of the coating material from vapor phase to liquid spray phase. By using a liquid coating solution with controlled spray parameters and solvent evaporation, the process achieves both large area coverage and precise thin coating control, resolving the contradiction between chamber size and adaptability.
2Area of stationary object
If film coating process is used, then large circuit boards can be coated, but the coating thickness is greater than desired for high precision RF performance
Solution Approach 1:
The patent uses a spray application process where the coating solution is delivered via pneumatic or hydraulic spray mechanism. This allows precise control of coating thickness through spray parameters while covering large areas, achieving both broad coverage and thin precise coating required for RF performance.
Solution Approach 2:
The patent utilizes phase transition of the solvent from liquid to vapor. The coating solution is applied as liquid, and the solvent evaporates to leave the polymer coating. This phase transition enables thin coating formation with controlled thickness, as the evaporating solvent carries excess material away and leaves only the required polymer layer.
3Ease of manufacture
If brush or dip coating is used, then coating can be applied to circuit boards, but the coating layer is not consistently thin enough to achieve desired conformal coating performance
Solution Approach 1:
The patent replaces manual brush or dip coating with an automated spray coating system. The spray process provides consistent, controllable coating thickness through pneumatic or hydraulic delivery, maintaining ease of manufacture while achieving the precise thin coating required for RF performance.
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 a thin, effective conformal coating that protects RF circuit boards from corrosion and short-circuits, maintaining performance by using a solvent that evaporates quickly, leaving a uniform, thin layer that adheres well and can be easily applied to larger surfaces, including both sides of the board.
Implementation Method 1
A predetermined time period is waited for substantial evaporation of the fluorinated solvent from the coated board, thus leaving behind a conformal coating of the amorphous fluorinated polymer on a board surface area
Data Source
AI summary
A method of, and system for, providing an amorphous fluorinated polymer conformal coating to an RF circuit board is described. A coating solution including the amorphous fluorinated polymer dissolved in a fluorinated solvent is provided. The coating solution is applied to the RF circuit board via a mechanically controlled fluid spray application device to produce a coated board. A predetermined time period is waited for substantial evaporation of the fluorinated solvent from the coated board, thus leaving behind a conformal coating of the amorphous fluorinated polymer on a board surface area.