Flexible Printed Circuit With Stacked Sub-Circuits And Integrated Pressure Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flexible printed circuits face challenges in integrating multiple signal lines and pressure sensors, leading to increased wiring complexity and potential signal interference, which complicates the design of flexible display devices like mobile phones and tablets.
Innovation Solution
A flexible printed circuit design featuring a stack of sub-circuit boards with a pressure sensor on one board, including a conductive film, adhesive layer, cover layer, and electromagnetic shielding layer, where the pressure sensor's electrode is part of the conductive film, allowing for reduced space occupation and improved signal distribution across multiple layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple signal lines and pressure sensors are integrated into a single flexible printed circuit board, then the functionality and versatility of the device are improved, but the wiring complexity and signal interference increase
Solution Approach 1:
The flexible printed circuit board is divided into a first circuit board and a second circuit board stacked together. The first circuit board contains signal lines for display signals and touch signals, while the second circuit board contains signal lines for fingerprint recognition signals. This segmentation separates different signal types into different spatial zones, reducing wiring complexity and signal interference while maintaining all required functionalities.
Solution Approach 2:
The patent transitions from a single-plane circuit board design to a three-dimensional stacked configuration. By arranging circuit boards in the vertical dimension (thickness direction), the design accommodates multiple signal lines and sensors without increasing planar wiring complexity, effectively resolving the contradiction between functionality integration and wiring complexity.
2Adaptability or versatility
If a pressure sensor is added to the flexible printed circuit board, then the sensing capability is improved, but the space occupation and device thickness increase
Solution Approach 1:
The pressure sensor electrode is merged with the conductive film that serves as a signal transmission line. The conductive film on the first circuit board functions dually as both an electrical conductor for signal transmission and as the electrode for the pressure sensor. This merging eliminates the need for separate electrode structures, reducing space occupation while maintaining sensing capability.
Solution Approach 2:
The conductive film is designed to serve multiple functions: it transmits electrical signals along the circuit board and simultaneously acts as the electrode for the pressure sensor. This multi-functionality reduces the overall component count and space requirements while enhancing the device's sensing capabilities.
3Productivity
If signal lines are densely arranged to accommodate multiple functions, then the wiring density is improved, but the signal interference between lines increases
Solution Approach 1:
Different signal lines are segmented into different circuit boards based on their functional groups. Display signals and touch signals are separated from fingerprint recognition signals through the stacked configuration. This spatial segmentation reduces electromagnetic interference between different signal types while maintaining high wiring density within each board.
Solution Approach 2:
The stacked configuration introduces a spatial intermediary (the gap between circuit boards) that acts as an electromagnetic isolation barrier. This physical separation reduces signal interference between different signal lines while allowing dense arrangement of conductors within each individual board layer.
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 design reduces the space required for the pressure sensor, facilitates the integration of multiple signal lines, and minimizes signal interference, enabling a larger battery capacity and enhanced flexibility in display device designs.
Implementation Method 1
an electromagnetic shielding layer arranged on a side of the cover layer away from the substrate film
Data Source
AI summary
A flexible printed circuit and a display device are provided. The flexible printed circuit includes: a plurality of sub-circuit boards arranged in a stack, wherein the plurality of sub-circuit boards include at least a first sub-circuit board and a second sub-circuit board; and a pressure sensor arranged on the first sub-circuit board, wherein the first sub-circuit board includes: a substrate film; a conductive film arranged on a side of the substrate film away from the second sub-circuit board; an adhesive layer arranged on a side of the conductive film away from the substrate film; a cover layer arranged on a side of the adhesive layer away from the substrate film; and an electromagnetic shielding layer arranged on a side of the cover layer away from the substrate film, wherein at least a part of the conductive film is formed as an electrode of the pressure sensor.