Fingerprint Sensor Dynamic Calibration Triggering
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Solution Overview
Problem
Fingerprint sensors face inefficiencies in power consumption and calibration accuracy due to regular time-based calibrations, which can lead to suboptimal performance under changing environmental conditions, such as humidity, temperature, and electromagnetic interference.
Innovation Solution
A method to dynamically initiate calibration operations based on changes in environmental parameters or anticipated events, such as user interactions or location changes, using integrated or external sensors to determine when a calibration is necessary, thereby optimizing power usage and ensuring accurate fingerprint capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous calibration is performed at given time intervals, then calibration accuracy is maintained, but power consumption increases unnecessarily when the sensor is unused for long periods
Solution Approach 1:
The calibration system transitions from static time-based scheduling to dynamic event-driven calibration. The calibration is triggered dynamically based on detected events (finger presence, environmental changes) rather than following a fixed schedule, allowing the system to adapt calibration frequency to actual usage conditions and reduce unnecessary power consumption during idle periods
Solution Approach 2:
The system uses the fingerprint sensor's own operational data and environmental sensors to automatically determine when calibration is needed. The sensor monitors its own usage patterns and environmental conditions, making autonomous decisions about calibration timing without requiring external control, thereby optimizing power consumption while maintaining accuracy
2Use of energy by moving object
If calibration time interval is increased to decrease power consumption, then power efficiency improves, but the risk increases that the sensor is not properly calibrated when needed
Solution Approach 1:
The system performs calibration in advance of actual fingerprint capture events by detecting triggering conditions (finger presence, environmental parameter changes) before the sensor is needed. This preliminary calibration ensures the sensor is ready when required, eliminating the risk of using uncalibrated data while maintaining long intervals between calibrations to save power
Solution Approach 2:
The system continuously monitors environmental parameters (temperature, humidity, electromagnetic field strength) and sensor usage status, using this feedback to dynamically adjust calibration timing. When feedback indicates changing conditions or upcoming usage, the system triggers calibration; when feedback shows stable conditions and idle state, the system extends calibration intervals to improve power efficiency
3Reliability
If calibration is performed at system startup and at regular intervals, then calibration coverage is ensured, but power consumption increases during periods of sensor inactivity
Solution Approach 1:
The system replaces continuous periodic calibration with event-driven periodic calibration. Instead of calibrating at fixed time intervals regardless of usage, the system calibrates periodically only when specific events occur (sensor activation, environmental changes), maintaining calibration coverage while eliminating power consumption during extended inactivity periods
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 approach enhances the power efficiency and reliability of fingerprint sensors by calibrating only when required, ensuring optimal performance under current conditions and reducing unnecessary power consumption during periods of inactivity.
Implementation Method 1
a capacitive fingerprint sensor where a fingerprint image is acquired by measuring a capacitive coupling between a finger placed on the sensor and the sensing element
Implementation Method 2
An electromagnetic field interacting with the sensor circuitry may induce power in circuits and connections, resulting in a shift in the change in electrical potential required to reach the analogue finger detect threshold
Implementation Method 3
Moist on the sensor can also be due to direct contact with water, e.g. after the user has taken a bath or when the device is used in rainy weather, or due to condensation of water from humid air at the sensor surface
Data Source
AI summary
There is provided a method of initiating a calibration operation of a fingerprint sensing device comprising an array of sensing elements for sensing a fingerprint pattern, the method comprising acquiring information indicative of a change of an environmental parameter influencing the operation of the fingerprint sensing device; and if the change is larger than a predetermined threshold value, performing a calibration operation of the fingerprint sensing device. There is also provided a method of initiating a calibration operation of a fingerprint sensing device comprising an array of sensing elements for sensing a fingerprint pattern, the method comprising: receiving information indicative of an event in a device in which the fingerprint sensing device is arranged; if the event is one of a group of predetermined events, performing a calibration operation of the fingerprint sensing device.