Phase Detector Calibration for Inductive Resonant Sensing
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Solution Overview
Problem
Existing mobile devices with mechanical buttons face issues such as aging, wear, and difficulty in making them waterproof, while virtual buttons lack the tactile feedback and sensitivity required for an optimal user experience.
Innovation Solution
A resonant phase sensing system using a resistive-inductive-capacitive sensor with a measurement circuit and incident/quadrature detector for accurate detection of user interactions, incorporating calibration methods to correct for non-idealities and drift, providing sensitive and reliable feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional force or pressure sensors are used to detect user interaction, then sensor sensitivity can be maintained, but power consumption increases and device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical force or pressure sensors with a resonant sensor system that uses electrical resonance frequency detection. The measurement circuit excites the sensor element electrically and detects changes in resonance frequency and quality factor, substituting mechanical sensing with electrical resonance-based sensing to reduce power consumption while maintaining sensitivity
Solution Approach 2:
The patent monitors changes in resonance frequency and quality factor parameters of the sensor element to detect user interactions. By tracking these dynamic electrical parameters rather than static force values, the system achieves high sensitivity with lower power consumption compared to traditional force sensors
2Measurement precision
If traditional force or pressure sensors are used to detect user interaction, then sensor sensitivity can be maintained, but device complexity increases
Solution Approach 1:
The patent combines the sensor element, excitation circuit, and measurement circuit into an integrated resonant sensing system. The sensor element serves dual purposes as both the sensing element and the resonant oscillator, eliminating the need for separate mechanical sensor components and reducing overall device complexity
Solution Approach 2:
The resonant sensor element performs multiple functions: it acts as the sensing element for detecting user interactions, serves as the resonant oscillator for frequency-based measurement, and functions as the test mass in the resonant system. This multi-functionality reduces the number of separate components needed
3Measurement precision
If incident/quadrature detector is used to measure resonance parameters, then measurement precision improves, but non-idealities and drift affect reliability
Solution Approach 1:
The patent performs calibration measurements before actual sensing operations to determine and store correction factors for gain and phase mismatches in the incident and quadrature channels. This preliminary calibration action compensates for systematic non-idealities, ensuring reliable measurements during subsequent operation
Solution Approach 2:
The system uses feedback from calibration measurements to adjust and correct the incident and quadrature channel signals. By continuously applying correction factors derived from calibration data, the system compensates for drift and non-idealities, maintaining measurement reliability over time
4Measurement precision
If calibration is performed to correct non-ideality between incident and quadrature channels, then measurement precision improves, but calibration complexity increases
Solution Approach 1:
The system performs self-calibration by automatically determining correction factors for gain and phase mismatches using built-in calibration routines. The calibration process is integrated into the device operation, eliminating the need for external calibration equipment or manual adjustment, thereby reducing calibration complexity
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
Enhances user interaction sensitivity and reliability, improving the user experience by providing tactile feedback similar to mechanical buttons while maintaining device durability and water resistance.
Implementation Method 1
a resonant sensor configured to sense a physical quantity
Implementation Method 2
measure one or more resonance parameters associated with the resonant sensor and indicative of the physical quantity using an incident/quadrature detector
Data Source
AI summary
A system may include a resonant sensor configured to sense a physical quantity, a measurement circuit communicatively coupled to the resonant sensor and configured to measure one or more resonance parameters associated with the resonant sensor and indicative of the physical quantity using an incident/quadrature detector having an incident channel and a quadrature channel and perform a calibration of a non-ideality between the incident channel and the quadrature channel of the system, the calibration comprising determining the non-ideality by controlling the sensor signal, an oscillation signal for the incident channel, and an oscillation signal for the quadrature channel; and correcting for the non-ideality.