Encapsulated Fingerprint Sensor Module for Thin Glass Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fingerprint sensor designs for electronic devices face challenges in achieving a cost-efficient, high-volume manufacturing process while maintaining mechanical robustness and integration simplicity, particularly when incorporated into thin display panels, as they often require complex and expensive silicon circuitry and suffer from performance degradation due to the thickness and electrical properties of the glass.
Innovation Solution
A fingerprint sensor module comprising a wrapped fingerprint sensor assembly with a flexible circuit subassembly around a rigid substrate, mounted on a PCB with a cutout to accommodate an ASIC, and encapsulated with non-conductive dielectric material, providing a robust and efficient self-contained module that can be easily integrated into host devices with a smooth, continuous surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fingerprint sensors are placed under chemically strengthened glass, then the sensor is protected and integrated into the display panel, but the thickness and electrical properties of the glass degrade the fingerprint sensor performance
Solution Approach 1:
The patent introduces an intermediary thin glass layer or encapsulant material between the fingerprint sensor and the chemically strengthened glass. This intermediary layer allows the sensor to be protected by the outer glass while maintaining optimal electrical properties for fingerprint detection, as the thin intermediary does not significantly degrade sensor performance
Solution Approach 2:
The glass structure is segmented into multiple layers: an outer chemically strengthened glass layer for protection, a thin intermediary layer for electrical optimization, and the fingerprint sensor layer. This segmentation allows each layer to fulfill its specific function without compromising the others
2Measurement precision
If the glass is locally thinned in the sensor area to improve performance, then fingerprint sensor performance improves, but the mechanical robustness of the entire host device panel is weakened
Solution Approach 1:
The glass panel is segmented into a thick outer layer for structural strength and a thin inner layer or localized region for sensor performance, allowing each zone to optimize its function without compromising the other
Solution Approach 2:
An intermediary support structure or reinforcement layer is introduced behind the thinned sensor region to maintain mechanical robustness while allowing the sensor area to be thin enough for optimal performance
3Adaptability or versatility
If a wrapped fingerprint sensor assembly is used to integrate into a cutout in the host device panel, then integration flexibility improves, but the difficulty of integrating the sensor core into a low cost module using industry standard manufacturing processes increases
Solution Approach 1:
The patent designs a universal module housing and PCB structure that can accommodate different sensor core sizes and types through standardized interfaces and cutouts, allowing the same manufacturing process to produce modules for various sensor configurations without requiring custom tooling for each sensor type
4Shape
If delicate silicon circuitry is placed directly behind a chemically thinned or milled section of the host device cover, then a smooth continuous outer surface is achieved, but the complexity and cost of manufacturing increases
Solution Approach 1:
An intermediary module housing and PCB structure is introduced between the sensor and the chemically thinned glass, allowing the sensor to be mounted on a standardized platform that can be manufactured using conventional processes, thereby reducing overall system complexity
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A fingerprint sensor module includes a fingerprint sensor assembly with a circuit element attached. The fingerprint sensor assembly is electrically connected to a printed circuit board (PCB) substrate with a cutout to accommodate the circuit element. The entire fingerprint sensor assembly and at least part of the PCB are encapsulated in a encapsulating material to produce a structurally robust fingerprint sensor module suitable for integration into an electronics device such as a smartphone or other "Internet of Things" (IOT) electronic device.