Embedding Devices in Flexible Printed Circuit Cavities
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Solution Overview
Problem
Current flexible printed circuit technologies face challenges in maintaining flexibility while embedding electronic devices, as they become less flexible with added layers and surface-mounted components, leading to increased rigidity, complexity, and poor thermal management, which hinders size, weight, and cost-effectiveness, as well as effective heat dissipation and electromagnetic interference protection.
Innovation Solution
A method of embedding electronic devices into flexible printed circuits by creating openings in the circuit layers, using thermally conductive adhesives, and filling with filler materials to maintain flexibility and enhance thermal conductivity, allowing for efficient heat dissipation and reduced bulkiness, while using automated roll-to-roll manufacturing for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If surface mounted devices are added to flexible circuit surfaces, then device functionality is improved, but the flexible circuit becomes more rigid and less flexible
Solution Approach 1:
The patent embeds electronic devices inside the flexible circuit board by creating cavities within the flexible substrate and placing devices within these cavities. The devices are nested within the flexible circuit structure rather than being mounted on the surface, allowing the flexible circuit to maintain its flexibility while incorporating device functionality. The flexible substrate is then sealed over the embedded devices, creating an integrated structure where devices are contained within the flexible circuit body.
2Adaptability or versatility
If multiple layers of metal and non-conductive substrates are added to the flexible printed circuit, then device support capability is improved, but flexibility is reduced
Solution Approach 1:
The patent transitions from surface-mounted device arrangement to embedded device arrangement within the flexible circuit board. By creating cavities within the flexible substrate and placing devices inside these cavities, the invention utilizes the third dimension (depth) rather than only surface area. This dimensional change allows multiple devices to be integrated within the flexible circuit body without adding multiple layers that would reduce flexibility, while still providing adequate device support capability.
3Temperature
If conventional heat sinks are attached to substrates or packaged SMDs, then heat dissipation is improved, but the assembly becomes bulky, heavy, and inflexible
Solution Approach 1:
The patent integrates thermal management functionality directly into the flexible circuit board structure by embedding thermally conductive materials within the flexible substrate itself. Rather than attaching separate heat sinks to the surface, the thermal management system is merged with the flexible circuit board, creating an integrated structure that provides heat dissipation without adding bulk, weight, or reducing flexibility. The thermally conductive material is incorporated within the flexible substrate layers, allowing heat to be conducted away from devices while maintaining the flexible nature of the overall assembly.
4Reliability
If rigid PCB technology is used to accommodate fragile components, then component protection is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies local quality by creating specific cavities within the flexible substrate at locations where device embedding is required, rather than making the entire flexible circuit board rigid. The flexible substrate maintains its flexibility in regions where embedding is not needed, while providing localized structural support and protection for embedded devices through the cavity structure and sealing process. This localized approach protects fragile components where needed while preserving the overall flexibility and simplicity of the flexible circuit board 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 solution enables a cost-effective, adaptable, and space-saving method for embedding multiple devices, maintaining flexibility, and improving thermal management and electromagnetic interference protection, allowing for efficient heat dissipation and reduced mechanical stresses.
Implementation Method 1
providing a thermally conducting adhesive on the upper surface of the second conductive layer, placing the pre-assembled electronic device into the opening to attach a first surface of the electronic device facing the second conductive layer to the second conductive layer via the thermally conductive adhesive
Data Source
AI summary
A flexible printed circuit assembly, having a first flexible printed circuit having a first conductive layer and a device that is connected the first conductive layer; and a second flexible printed circuit having a second conductive layer, an insulating center layer, and a third conductive layer, the insulating center layer arranged in-between the second and the third conductive layers, the second conductive layer and the insulating center layer being removed to form an opening to expose an upper surface of the third conductive layer, wherein the first flexible printed circuit is arranged such that the device is accommodated inside the opening, a lower surface of the device being in thermal connection with the third conductive layer, and the first conductive layer is arranged to be in electrical connection with the second conductive layer.