Ultrasonic Touch Sensing Calibration for Temperature Drift
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Solution Overview
Problem
Ultrasonic touch sensing devices inaccurately detect touch events due to temperature variations, causing continuous false detection as the intensity of the touch sensing signal fails to return to the reference level after a touch event ends.
Innovation Solution
A method and device that incorporate a temperature detecting circuit and microprocessor to generate temperature parameters, allowing for calibration of the reference signal when temperature variations exceed a preset range, ensuring accurate detection by adjusting the reference signal based on signal strength and temperature variance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference signal level is used for touch detection without temperature calibration, then the device complexity is reduced, but the measurement precision deteriorates due to temperature variations causing false touch detection
Solution Approach 1:
A temperature detecting circuit is introduced as an intermediary component to measure temperature variations. This circuit generates temperature parameters that serve as a mediator between the physical temperature environment and the ultrasonic touch sensing system, enabling indirect compensation for temperature effects on signal intensity without directly modifying the core sensing mechanism
Solution Approach 2:
The system dynamically adjusts the reference signal level based on temperature parameters. When temperature variations are detected, the reference signal is calibrated to compensate for the expected signal intensity changes, transforming the static reference level into a temperature-dependent variable that maintains detection accuracy across different thermal conditions
2Measurement precision
If temperature calibration is implemented continuously, then the measurement precision is improved, but the use of energy increases due to continuous temperature monitoring and signal calibration
Solution Approach 1:
Instead of continuous calibration, the system performs temperature-based reference signal calibration periodically or event-driven. The temperature detecting circuit monitors temperature parameters, and calibration is triggered only when temperature variations exceed a threshold or when specific conditions are met, reducing unnecessary calibration operations and associated energy consumption while maintaining detection accuracy
3Measurement precision
If the reference signal level is lowered to account for temperature decay, then the measurement precision is improved, but the reliability deteriorates due to continuous false detection of touch events
Solution Approach 1:
The system establishes a feedback mechanism where temperature parameters continuously inform reference signal calibration. The temperature detecting circuit provides real-time temperature data, which feeds back to adjust the reference signal level dynamically. This closed-loop feedback ensures that the reference signal adapts to temperature changes without causing false detections, as the calibration is based on actual measured temperature rather than predetermined adjustments
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 prevents continuous false detection of touch events by calibrating the reference signal, ensuring accurate sensing by correlating signal strength with temperature parameters, thus improving the reliability of ultrasonic touch sensing devices.
Implementation Method 1
ultrasonic touch sensing device includes a piezoelectric sensing layer for generating ultrasonic wave
Implementation Method 2
a piezoelectric detecting layer for receiving the reflected ultrasonic wave
Data Source
AI summary
A method of calibrating touch sensing applicable to a microprocessor of an ultrasonic touch sensing device, in which the ultrasonic touch sensing device is for generating a touch sensing signal according to a ultrasonic wave, and the method includes: receiving the touch sensing signal; measuring temperature of the ultrasonic touch sensing device to generate multiple temperature parameters; if a variation tendency of the temperature parameters is downward, and if a level of the touch sensing signal lower than a level of a reference signal is first detected, storing the level of the touch sensing signal as a first signal strength and reporting a touch event is detected; and if the variation tendency of the temperature parameters is downward, and if the level of the touch sensing signal lower than the level of the reference signal is not first detected, calibrating the reference signal according to the touch sensing signal.