Embedded Optical Waveguides on PCBs with Dry-Film Planarization
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Solution Overview
Problem
The integration of optical components into printed circuit boards (PCBs) often results in optical loss due to surface topography variations in the substrate, which affects the performance of embedded optical waveguides.
Innovation Solution
A dry-film layer is applied to the PCB substrate using lamination techniques, providing a planar surface for forming optical waveguides with a core and clad structure, and surface treatments like mechanical polishing or plasma discharge are used to enhance adhesion and reduce optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical waveguides are formed directly on the printed circuit board substrate, then the manufacturing process is simplified, but optical loss increases due to surface topography variations
Solution Approach 1:
A dry-film layer is introduced as an intermediary between the PCB substrate and the optical waveguide. This dry-film layer has a smooth surface that reduces optical loss while maintaining the simplified manufacturing process of direct waveguide formation on substrate.
2Loss of energy
If a dry-film layer is applied to the PCB substrate, then optical loss is reduced due to surface smoothing, but the manufacturing process becomes more complex
Solution Approach 1:
A thin dry-film layer is applied to the PCB substrate to provide surface smoothing. The thin-film approach reduces optical loss while minimizing the increase in manufacturing complexity compared to thicker or more complex surface preparation methods.
3Strength
If surface treatments like mechanical polishing or plasma discharge are applied to the dry-film layer, then adhesion is enhanced, but the manufacturing process time increases
Solution Approach 1:
Surface treatments such as mechanical polishing or plasma discharge are applied to the dry-film layer before forming the optical waveguide. This preliminary action enhances adhesion in advance, preventing future delamination issues and reducing the need for corrective actions later in the manufacturing process.
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 results in optical waveguides with improved optical loss characteristics by smoothing the substrate surface and enhancing adhesion, leading to more efficient signal transmission.
Implementation Method 1
The dry-film layer may be applied to the printed circuit board substrate by a lamination process, such as vacuum lamination, hot-roll lamination or cut-sheet lamination.
Implementation Method 2
The surface of the dry-film layer may be treated before formation of the clad to improve adhesion to the waveguide. Such treating may include, for example, one or more of mechanical polishing or treatment with corona discharge, flame, ozone or plasma.
Data Source
Figure 1A~2B
Figure 2C~2E
Figure 3
AI summary
Provided are methods of forming printed circuit boards having optical functionality. The methods involve applying a dry-film to a printed circuit board substrate and forming an optical waveguide over the dry-film. The invention finds particular applicability in the electronics and optoelectronics industries.