Fingerprint Sensor Conductive Shielding for Display Noise Isolation
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Solution Overview
Problem
Fingerprint sensors in display devices face interference from noise signals generated by the display panel, which affects the accuracy of fingerprint recognition.
Innovation Solution
A fingerprint sensor design that includes a light-blocking conductive layer with holes, a substrate, and a conductive connector, which is connected to a predetermined voltage, to reduce noise interference by preventing scan signals from the display panel from coupling with the sensing signals through parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-blocking conductive layer is disposed on the sensor pixel, then noise interference from display panel signals is reduced, but device complexity increases due to additional layers and connections
Solution Approach 1:
A light-blocking conductive layer is introduced as an intermediary component between the display panel and the sensor pixel. This conductive layer acts as a mediator that blocks noise signals from the display panel while allowing light to pass through to the sensor, thereby reducing noise interference without fundamentally changing the core sensing function
Solution Approach 2:
The conductive layer is segmented into a patterned structure with holes or openings rather than being a continuous layer. This segmentation allows light to pass through specific regions to the sensor pixel while maintaining the noise-blocking function in other regions, optimizing both noise reduction and light transmission
2Measurement precision
If the light-blocking conductive layer is electrically connected to a conductive connector with predetermined voltage, then sensing signal accuracy is improved by stabilizing voltage, but manufacturing precision requirements increase
Solution Approach 1:
The conductive layer is electrically connected to a conductive connector that provides a predetermined voltage (such as ground potential). This equipotential connection stabilizes the electrical potential of the conductive layer, preventing noise signal coupling and improving the accuracy of sensing signals by maintaining a stable reference potential
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 effectively minimizes noise interference, enhancing the accuracy of fingerprint recognition by stabilizing the voltage applied to the light-blocking conductive layer, thereby reducing adverse effects from scan signals on the sensing signals.
Implementation Method 1
a sensor pixel disposed on the substrate and including a light sensing element through which a sensing current flows according to an amount of incident light
Implementation Method 2
a light-blocking conductive layer disposed on the sensor pixel and including a plurality of holes
Data Source
AI summary
A fingerprint sensor includes a substrate, a sensor pixel disposed on the substrate and including a light sensing element through which a sensing current flows according to an amount of incident light, a light-blocking conductive layer disposed on the sensor pixel and including a plurality of holes, a first fingerprint pad disposed on the substrate, and a conductive connector connected to the first fingerprint pad and to which a predetermined voltage is applied. The light-blocking conductive layer is electrically connected to the conductive connector.