Flexible Printed Circuit Board Overlap for Touch Detection Sensitivity
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Solution Overview
Problem
Current liquid crystal display devices with touch detection capabilities face challenges in achieving high detection sensitivity and efficient manufacturing processes, particularly in integrating touch detection systems without compromising the display's performance and visibility.
Innovation Solution
A detection device configuration featuring a substrate with detection electrodes, flexible printed circuit boards, and a shield layer, where the flexible printed circuit boards are electrically connected and arranged to overlap, allowing for improved detection sensitivity and simplified manufacturing by maintaining the detection electrode and shield layer at a constant potential during display writing and detection periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch detection device is mounted on a liquid crystal display device, then touch detection capability is achieved, but detection sensitivity and manufacturing efficiency are compromised
Solution Approach 1:
The patent divides the flexible printed circuit board into multiple segments (first FPC and second FPC) that are arranged side-by-side with overlapping terminals. This segmentation allows for optimized electrical connection paths and reduced parasitic capacitance, thereby improving detection sensitivity while maintaining touch detection functionality.
Solution Approach 2:
The patent transitions from a conventional single-plane FPC connection to a three-dimensional arrangement where terminals overlap in plan view but are connected through vertical stacking. This dimensional change enables reduced connection resistance and optimized signal paths, resolving the contradiction between maintaining detection capability and improving sensitivity.
2Reliability
If conventional FPC connection methods are used, then electrical connection is achieved, but connection resistance and parasitic capacitance are high
Solution Approach 1:
The patent merges the first FPC and second FPC into a integrated structure with overlapping terminals that are electrically connected. This merging creates parallel current paths and reduces overall connection resistance, while the compact overlapping arrangement minimizes parasitic capacitance, thereby improving electrical connection quality.
Solution Approach 2:
The overlapping terminal structure acts as an intermediary between the detection electrode and the external circuitry. This intermediate configuration optimizes the electrical path by reducing connection resistance and minimizing parasitic capacitance effects, thereby improving signal integrity for touch detection.
3Ease of manufacture
If the detection electrode and shield layer potentials are not maintained constant, then manufacturing is simpler, but detection accuracy deteriorates
Solution Approach 1:
The patent implements equipotentiality by maintaining the detection electrode and shield layer at constant potentials during both display writing and detection periods. This is achieved through the optimized FPC connection structure that provides stable electrical connections, thereby ensuring detection accuracy without significantly complicating the manufacturing process.
Data Source
AI summary
A detection device includes: a substrate, a detection electrode on a first surface of the substrate, a first flexible printed circuit board electrically connected to the detection electrode, a shield layer on a second surface opposite the first surface of the substrate, and a second flexible printed circuit board electrically connected to the shield layer on the second surface; wherein the first flexible printed circuit board has a first terminal on a side of a first side extending outward from the substrate, the second flexible printed circuit board has a second terminal on a side of a second side extending outward from the substrate, the first flexible printed circuit board and the second flexible printed circuit board are arranged side-by-side along a side of the substrate.