Fingerprint Sensor Folded Structure Reduces Noise
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Solution Overview
Problem
Fingerprint sensors experience degraded touch sensitivity due to increased noise resulting from the distance difference between the sensing part and the chip, which affects their reliability and performance.
Innovation Solution
The design incorporates a fingerprint sensor with substrates that include flexible and optically isotropic materials, such as sapphire, and a folded structure to minimize the distance between the sensing parts and chips, using anisotropic conductive films and chip-on-film technology to ensure efficient connection and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sensing part is positioned away from the chip, then the layout flexibility is improved, but the touch sensitivity deteriorates due to increased noise from distance difference
Solution Approach 1:
The patent employs flexible substrates (first substrate and second substrate) that allow the sensing part and chip to be connected through folded configurations. This enables the sensing part to be positioned away from the chip for layout flexibility while maintaining a short effective distance through the folded film structure, thereby preserving touch sensitivity.
2Reliability
If the distance between sensing part and chip is reduced, then noise is reduced and touch sensitivity is improved, but the layout flexibility and ease of connection are worsened
Solution Approach 1:
The patent transitions from a planar layout to a three-dimensional folded structure. The sensing part and chip are positioned on different substrates that are folded relative to each other, creating a spatial configuration that maintains short distance while providing layout flexibility and ease of connection.
Solution Approach 2:
The patent introduces flexible substrates and anisotropic conductive films as intermediary elements between the sensing part and the chip. These intermediaries enable connection while maintaining short distance, resolving the contradiction between proximity requirements and layout flexibility.
3Reliability
If flexible substrates and folded structures are used, then the distance between sensing part and chip is minimized reducing noise, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into the flexible substrate structure: it serves as both the mounting platform for the sensing part and chip, and as the connecting element that maintains short distance through folding. This merging reduces overall structural complexity despite the folded configuration.
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 configuration enhances the touch sensitivity and reliability of the fingerprint sensor by minimizing noise and maintaining a short distance between the sensing parts and chips, improving the overall performance.
Implementation Method 1
using anisotropic conductive films and chip-on-film technology to ensure efficient connection and reduce noise
Data Source
AI summary
A fingerprint sensor includes a first substrate, a second substrate on the first substrate, a first electrode and a first chip on the first substrate and a second electrode and a second chip on the second substrate. The first substrate includes a first area and a second area, the second substrate includes a third area and a fourth area, the first electrode is provided on the first area, the first chip is provided on the second area, the second electrode is provided on the third area, and the second chip is provided on the fourth area.