Multi-Directional Magnetic Sensing for Reliable Cover Trigger Detection

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Solution Overview

Problem

Magnetic sensor apparatuses in electronic equipment, such as mobile phones and tablets, are susceptible to interference from internal and external magnetic fields, leading to inadvertent triggering of functions due to monitoring of magnetic fields in a single direction, especially when used with protective cases that complicate the magnetic field changes.

Innovation Solution

Incorporating at least two magnetic field detectors that sense magnetic fields in different directions, with a control circuit connected to the motherboard, to send a sensor signal only when external magnetic induction meets a preset threshold in each direction, thereby improving precision and avoiding inadvertent triggers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single magnetic field detector is used to monitor magnetic field in one direction, then the device complexity is reduced, but the measurement precision deteriorates due to susceptibility to interference from internal and external magnetic fields

Engineering Contradiction:
Improvemagnetic field sensing precisionVSAvoidmagnetic sensor apparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dimensionality change by transitioning from single-direction magnetic field detection to multi-directional detection. Specifically, it uses at least two magnetic field detectors arranged in different spatial directions (e.g., perpendicular to each other) to detect magnetic field components along different axes. This multi-dimensional approach allows the system to distinguish between magnetic fields originating from different sources (internal vs. external) by analyzing the directional characteristics, thereby improving measurement precision without excessive complexity increase.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent segments the magnetic field detection function into multiple independent detectors, each responsible for detecting magnetic field components in specific directions. By dividing the detection task across multiple sensors with different sensing orientations, the system can analyze the magnetic field from multiple perspectives and filter out interference through comparative analysis, thus improving overall measurement accuracy.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a magnetic sensor apparatus monitors magnetic field in one direction, then the ease of operation is maintained, but the reliability deteriorates due to inadvertent trigger of functions

Engineering Contradiction:
Improvefunction trigger reliabilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback mechanisms where the control circuit continuously monitors the outputs from multiple magnetic field detectors and dynamically adjusts the triggering logic. By comparing the magnetic field readings from different directions and analyzing their temporal and spatial relationships, the control circuit can distinguish between legitimate triggers (such as protective case opening) and false triggers (caused by internal magnets or external interference), thereby improving reliability through intelligent feedback-based decision making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary analysis of magnetic field patterns from multiple detectors before triggering any function. By pre-establishing threshold values and trigger conditions based on multi-directional magnetic field characteristics, the system can predict and prevent false triggers before they occur, ensuring more reliable function activation only when genuine external magnetic field changes are detected.

Inventive Principle:
Principle #10Preliminary action

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 solution enhances the precision of magnetic sensing, reducing false triggers and improving the user experience with protective cases by monitoring magnetic induction in multiple directions, ensuring accurate control of electronic equipment functions.

Implementation Method 1

Any two of the at least two magnetic field detectors sense a magnetic field respectively in two sensing directions differing from one another

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

The control circuit sends a sensor signal to the motherboard in response to determining that external magnetic induction sensed by each of the at least two magnetic field detectors is no less than a preset threshold

Methodology Applied
Scientific EffectMagnetic induction detection: Electromagnetic Induction

Data Source

PatentEP3805894A1Electronic equipment, system for protecting electronic equipment, method for controlling electronic equipment, storage medium, and computer program
Publication Date: 2021.04.14 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3805894A1 patent drawingFigure 1
  • EP3805894A1 patent drawingFigure 2A~2B
  • EP3805894A1 patent drawingFigure 3A~3B

AI summary

Electronic equipment (1) includes an equipment body (11) and a magnetic sensor apparatus (12) assembled to the equipment body (11). The magnetic sensor apparatus (12) is provided with at least two magnetic field detectors (121). Any two magnetic field detectors (121) sense a magnetic field respectively in two different sensing directions. A control circuit (122) sends a sensor signal to a motherboard (111) only when each magnetic field detector (121) senses, in a respective sensing direction per se, external magnetic induction no less than a respective preset threshold corresponding to the each magnetic field detector (121). The motherboard (111) sends a control signal to control the equipment body (11) according to the sensor signal.