Fingerprint Recognition Touch Sensor with Segmented Electrodes
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Solution Overview
Problem
Existing touch sensors for mobile devices and electronic apparatuses face challenges in efficiently performing both high-resolution fingerprint recognition and touch sensing, leading to increased power consumption and scanning time, especially when switching between these modes.
Innovation Solution
A touch sensor design that divides transmitting and receiving lines into groups, allowing for distinct operating modes for fingerprint recognition and touch sensing, with adjustable voltage levels and circuit configurations to optimize sensitivity and resolution based on the mode, enabling separate and simultaneous signal processing for improved accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single touch sensor structure is used for both fingerprint recognition and touch sensing, then device complexity is reduced, but measurement precision and sensitivity are compromised
Solution Approach 1:
The touch sensor is divided into two distinct sensor structures: a first touch sensor dedicated to fingerprint recognition and a second touch sensor dedicated to touch sensing. This segmentation allows each sensor to be optimized for its specific function, with the first sensor achieving high measurement precision for fingerprint patterns while the second sensor provides accurate touch position detection, thereby resolving the contradiction between structural simplicity and measurement precision.
2Manufacturing precision
If the same sensing electrodes are used for both fingerprint recognition and touch sensing, then manufacturing precision requirements are reduced, but sensitivity for fingerprint recognition is insufficient
Solution Approach 1:
The sensing electrodes are segmented into two separate sets: first sensing electrodes for fingerprint recognition and second sensing electrodes for touch sensing. The first sensing electrodes are specifically arranged to detect fingerprint patterns with high sensitivity, while the second sensing electrodes are optimized for touch position detection. This segmentation enables each electrode set to be independently optimized for its specific sensing requirement without compromising manufacturing feasibility.
Solution Approach 2:
Different electrode configurations are applied to different functional zones: the first sensing electrodes are arranged in a pattern optimized for capturing fingerprint ridge and valley patterns, while the second sensing electrodes are positioned to detect touch contact points. This local differentiation of electrode quality and arrangement allows each sensing system to achieve its required performance characteristics.
3Measurement precision
If high voltage is applied to improve fingerprint recognition sensitivity, then measurement precision improves, but power consumption increases
Solution Approach 1:
The power supply system is segmented to provide different voltage levels to different sensors: a first voltage applied to the first sensing electrodes for fingerprint recognition and a second voltage applied to the second sensing electrodes for touch sensing. This allows the fingerprint recognition sensor to receive higher voltage for improved sensitivity and measurement precision, while the touch sensing sensor operates at lower voltage to minimize power consumption, thereby resolving the contradiction between measurement precision and energy usage.
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 design allows for precise fingerprint recognition with high sensitivity and efficient touch sensing with reduced power consumption, enabling seamless switching between modes without compromising resolution or accuracy, thus enhancing user interaction and device performance.
Implementation Method 1
a control circuit configured to apply a first voltage to a first sensing electrode and a second voltage to a second sensing electrode, the second voltage being different from the first voltage, and to detect an electrical property of the first sensing electrode and the second sensing electrode
Data Source
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AI summary
A touch sensor includes a plurality of parallel transmitting lines extending in a first direction, a plurality of parallel receiving lines extending in a second direction crossing the first direction, and a transmitting driver configured to, in a first mode, apply first driving signals of a first voltage, to the plurality of transmitting lines, and in a second mode, apply second driving signals of a second voltage, to the plurality of transmitting lines, the second voltage being different than the first voltage. The touch sensor further includes a signal output unit configured to receive touch signals from the plurality of receiving lines.