Ultrasonic Sensor Array Recalibration for Screen Protector Changes
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Solution Overview
Problem
Ultrasonic sensor systems face performance degradation due to the installation, removal, or replacement of screen protectors, which affect imaging quality and signal integrity.
Innovation Solution
The system detects the presence of a screen protector and recalibrates the ultrasonic sensor array by adjusting parameters such as range gate delay (RGD) and performing background calibration to maintain optimal signal-to-noise ratio (SNR) and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screen protector is installed over the ultrasonic sensor array, then the display screen is protected, but the imaging quality and signal integrity of the ultrasonic sensor degrade
Solution Approach 1:
The system detects changes in ultrasonic signal parameters (amplitude, phase, time of flight) caused by screen protector installation and recalibrates accordingly. The controller adjusts range gate delay (RGD) and performs background calibration to compensate for the screen protector's acoustic properties, maintaining measurement precision despite the added layer.
Solution Approach 2:
The system continuously monitors ultrasonic signal characteristics and uses this feedback to detect screen protector presence. Based on the detected changes in signal integrity, the system automatically triggers recalibration procedures to maintain optimal imaging quality while the screen protector remains in place.
2Strength
If a screen protector is installed over the ultrasonic sensor array, then the display screen is protected, but the signal-to-noise ratio of the ultrasonic sensor decreases
Solution Approach 1:
The system adjusts ultrasonic transmission parameters including range gate delay (RGD) to account for the screen protector's acoustic impedance. By modifying these parameters, the system optimizes the signal-to-noise ratio despite the presence of the screen protector, ensuring reliable fingerprint sensing.
Solution Approach 2:
The system uses the screen protector's acoustic properties (which initially cause signal degradation) as a detection mechanism. By analyzing the specific changes in ultrasonic signal characteristics caused by the screen protector, the system can detect its presence and automatically adjust calibration parameters to compensate, converting the harmful effect into a useful detection signal.
3Measurement precision
If the ultrasonic sensor array is recalibrated to accommodate screen protector changes, then imaging performance is maintained, but additional processing time and computational resources are required
Solution Approach 1:
The system performs background calibration in advance to establish baseline ultrasonic signal characteristics. When screen protector installation is detected, the system uses this pre-computed baseline to quickly determine the nature and extent of recalibration needed, reducing the time required for full recalibration procedures.
Solution Approach 2:
Instead of performing complete recalibration every time a screen protector change is detected, the system performs partial recalibration by adjusting only the specific parameters that are affected (such as range gate delay and background reference values). This selective approach maintains imaging performance while minimizing the time and computational resources required.
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 mitigates the adverse effects of screen protector installation or removal by enhancing signal quality and maintaining consistent imaging performance.
Implementation Method 1
a transmitter to generate and send an ultrasonic wave through a transmissive medium and towards an object to be detected
Implementation Method 2
an ultrasonic sensor array configured to detect portions of the ultrasonic wave that are reflected from the object
Implementation Method 3
detect portions of the ultrasonic wave that are reflected from the object
Implementation Method 4
The piezoelectric layer may convert vibrations caused by ultrasonic reflections into electrical output signals
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
Techniques for operating an ultrasonic sensor array, the ultrasonic sensor array disposed under a platen, include: making a determination whether or not to recalibrate the ultrasonic sensor array based on whether a first screen protector disposed above the platen has been removed or replaced by a second screen protector; and recalibrating the ultrasonic sensor array, when the determination is to recalibrate the ultrasonic sensor array. In some cases, the techniques include prompting a user to indicate whether or not the screen protector has been changed or removed, and recalibrating the ultrasonic sensor array only after confirmation from the user.