Laser Direct Structuring for Multi-Layer Curved Circuit Boards
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Solution Overview
Problem
Existing methods for manufacturing circuit boards struggle to create multiple-layer structures on 3-dimensional free curved surfaces due to difficulties in copper foil adhesion and uniform patterning, limiting the production of complex electronic devices like antennas and speakers to single-layer designs.
Innovation Solution
A method using Laser Direct Structuring (LDS) for injection-molded materials, involving substrate coating, laser irradiation, circuit pattern formation, and repeated plating and paint coating to create multiple-layer circuits on curved surfaces, with preformed holes and side surfaces for electrical contact, enabling the formation of laminated circuits on metal, glass, ceramic, or rubber substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-clad circuit patternization is used for multiple-layer structure, then circuit functionality is achieved, but adhesion and uniformity of patterning deteriorate on 3-dimensional free curved surfaces
Solution Approach 1:
The patent replaces the mechanical copper foil adhesion process with a chemical etching process. Instead of relying on mechanical adhesion of copper foil to curved surfaces, the invention uses photoresist coating followed by chemical etching to create circuit patterns directly on the substrate, eliminating the adhesion problem inherent in mechanical copper foil application on 3-dimensional curved surfaces.
Solution Approach 2:
The patent changes the manufacturing parameters from mechanical copper foil application to a chemical process involving photoresist coating, drying, and etching. This parameter change allows for uniform patterning on curved surfaces by controlling the chemical reaction rather than relying on mechanical adhesion, thereby improving patterning uniformity while maintaining circuit functionality.
2Ease of manufacture
If single-layer wiring is manufactured using LDS method, then manufacturing simplicity is maintained, but device complexity and functionality are limited
Solution Approach 1:
The patent divides the circuit board into multiple layers, with each layer containing specific circuit patterns. The segmentation is achieved through sequential photoresist coating, laser irradiation, and etching processes for each layer. This allows complex electronic devices to be manufactured by stacking multiple functional layers, thereby increasing device versatility while maintaining manufacturing simplicity through standardized layer-by-layer processing.
Solution Approach 2:
The patent transitions from single-layer (2D) circuit design to multi-layer (3D) circuit architecture. By adding the vertical dimension through multiple stacked layers, the invention enables complex electronic devices with enhanced functionality while maintaining manufacturing simplicity through repeated application of the same layer-by-layer process sequence.
3Adaptability or versatility
If multiple-layer circuit structure is formed on curved surfaces, then device complexity and functionality are improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the entire curved surface with photoresist material before laser irradiation and etching. This preliminary coating step simplifies the subsequent manufacturing process by providing a uniform base layer that can be selectively removed to reveal circuit patterns, thereby reducing the complexity of forming multiple layers on curved surfaces compared to direct copper foil application.
Solution Approach 2:
The patent employs self-service through the self-aligning nature of the photoresist coating process. The photoresist automatically conforms to the curved surface geometry, and the laser irradiation pattern is self-aligned to the pre-formed photoresist layer. This self-service mechanism eliminates the need for complex alignment procedures between layers, thereby reducing manufacturing process complexity while enabling multiple-layer circuits on curved surfaces.
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 approach facilitates the manufacturing of 3-dimensional free curved-surface circuit boards, allowing for the production of complex electronic devices such as MRI coils, touch sensors, and LEDs, and enables soldering and surface mount technologies, providing reliable electrical contact between layers.
Implementation Method 1
each laser irradiation, each layer forming a circuit pattern
Implementation Method 2
the plating of the circuit pattern
Data Source
AI summary
A method of forming a multi-layer circuit on a curved substrate includes forming, by a laser direct structuring process, a first layer of the multi-layer circuit on a first surface of the curved substrate. The method includes applying a first layer of paint to the first layer of the multi-layer circuit. The method includes forming, by the laser direct structuring process, a second layer of the multi-layer circuit on the first layer of the paint and electrically coupled to the first layer of the multi-layer circuit. The method includes applying a second layer of paint over the second layer of the multi-layer circuit and forming, by the laser direct structuring process, a third layer of the multi-layer circuit on the second layer of the paint and electrically coupled to the second layer of the multi-layer circuit.