Force Sensor Calibration for Portable Touch Displays
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Solution Overview
Problem
Existing touch-sensitive displays in portable electronic devices face challenges in accurately determining touch locations due to mechanical distortions and the need for continuous calibration, especially as devices shrink in size.
Innovation Solution
A method involving an actuator that applies a known force to the touch-sensitive display, measuring the resulting force with a sensor, and calibrating the sensor based on this force when no touch is detected, ensuring accurate touch location determination and maintaining sensor accuracy over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of portable electronic devices is decreased to improve portability, then device compactness is improved, but touch location detection accuracy deteriorates due to increased mechanical distortion effects
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the characteristics of the test force applied during calibration. The system varies the magnitude and distribution of the test force to account for mechanical distortions in smaller devices, thereby maintaining touch location detection accuracy despite reduced device size. This is achieved by modifying the calibration parameters based on the specific mechanical properties of the compact device structure.
2Ease of operation
If force sensors are used to detect touch location, then touch detection capability is improved, but sensor accuracy deteriorates over time due to mechanical distortion and drift
Solution Approach 1:
The patent implements preliminary action by performing calibration of the force sensors before actual touch detection operations. A test force is applied to the display in advance to establish baseline calibration parameters that account for mechanical distortions. This preliminary calibration step ensures that subsequent touch location measurements remain accurate despite sensor drift or mechanical variations in the device structure.
Solution Approach 2:
The system employs feedback by continuously monitoring the relationship between applied test force and sensor response. During calibration, the actual sensor measurements are compared against expected values, and calibration parameters are adjusted based on this feedback. This closed-loop approach compensates for sensor drift and mechanical distortion, maintaining long-term accuracy of touch location detection.
3Measurement precision
If calibration is performed continuously to maintain sensor accuracy, then measurement precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent applies periodic action by performing calibration at specific intervals rather than continuously. The system schedules calibration operations to occur at predetermined times, such as during device initialization or at scheduled maintenance intervals. This periodic approach maintains sensor accuracy while significantly reducing the complexity and power consumption associated with continuous calibration operations.
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 accuracy and reliability of touch location detection on portable electronic devices by compensating for mechanical distortions and drift in force sensors, improving user interaction and device performance even as devices decrease in size.
Implementation Method 1
applying, utilizing an actuator within the portable electronic device, a force on the touch-sensitive display of the portable electronic device; measuring, utilizing a force sensor, a value resulting from the force at the force sensor
Data Source
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AI summary
A method includes applying, utilizing an actuator of a portable electronic device, a force of a known magnitude to a touch-sensitive display of the portable electronic device, measuring a value resulting from the force at a force sensor, and calibrating the force sensor based on the value and the magnitude of the force.