Magnetometer Lid Angle Sensing for Vibration-Immune Device Control
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Solution Overview
Problem
Existing methods for measuring the lid angle of portable devices, such as notebooks and smartphones, are unreliable due to reliance on accelerometers which are sensitive to linear accelerations and environmental vibrations, especially when the device is held or moved, leading to imprecise measurements.
Innovation Solution
The use of magnetometers to generate signals indicative of the relative orientation between hardware elements, with a processing unit calculating a calibration parameter and reliability value to determine a reliable lid angle, allowing for accurate control of device functions regardless of orientation or movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are used to measure lid angle, then the measurement can be performed with simple hardware, but the measurement becomes unreliable when the device is moved or subjected to vibrations
Solution Approach 1:
The patent replaces accelerometers (mechanical sensing system) with magnetometers (electromagnetic sensing system) to measure lid angle. Magnetometers detect magnetic field orientation rather than experiencing linear accelerations, thereby eliminating sensitivity to vibrations and movements while maintaining measurement capability.
Solution Approach 2:
The patent changes the measurement parameter from acceleration-based detection to magnetic field-based detection. By measuring the orientation of magnetic field vectors instead of acceleration forces, the system achieves vibration immunity while continuously tracking lid angle through magnetic orientation changes.
2Measurement precision
If accelerometers are used for lid angle detection, then the device structure remains simple, but the measurement is inaccurate when the device is held in vertical position
Solution Approach 1:
The patent makes the measurement system universal by using magnetometers that can accurately determine lid angle in any device orientation (horizontal, vertical, tilted). The magnetic field reference frame provides a consistent reference regardless of device posture, enabling reliable measurement across all orientations unlike acceleration-based systems.
3Measurement precision
If magnetometers are used to measure lid angle, then immunity to linear accelerations and vibrations is achieved, but additional calibration procedures are required
Solution Approach 1:
The patent performs calibration procedures in advance to establish baseline magnetic field characteristics and device geometry parameters. By pre-calibrating the system during manufacturing or initial setup, the complex calibration requirements are satisfied beforehand, allowing the device to operate with high measurement reliability without requiring complex real-time calibration mechanisms.
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 provides a reliable and adaptive measurement of the lid angle, reducing costs and immunity to linear accelerations and drift, ensuring accurate orientation detection even when the device is held like a book or subjected to vibrations.
Implementation Method 1
generating, by the first magnetometer and by the second magnetometer, first signals that are indicative of measurements of a magnetic field external to the electronic apparatus
Data Source
AI summary
A method is provided for controlling an electronic apparatus on the basis of a value of a lid angle between a first hardware element accommodating a first magnetometer and a second hardware element accommodating a second magnetometer. The method includes acquiring, through the magnetometers, first signals representing an orientation of the hardware elements. A calibration parameter indicative of a condition of calibration of the magnetometers is generated on the basis of the first signals. A reliability value indicative of a condition of reliability of the first signals is generated on the basis of the first signals. A first intermediate value of the lid angle is calculated on the basis of the first signals. A current value of the lid angle is calculated on the basis of the calibration parameter, of the reliability value, and of the first intermediate value, and the electronic apparatus is controlled on the basis of the current value.