Closure Sensor Layout Using Ferromagnetic Flux Guidance
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Solution Overview
Problem
Existing electronic device closure sensors face challenges in reliably detecting the open or closed position, often due to interference from other magnetic components and require multiple or strong magnets, which increases complexity, cost, and energy consumption.
Innovation Solution
An extended closure sensor design utilizing a first magnet, a ferromagnetic material, and a magnetic sensor, where a second magnet's adjustable position causes different magnetic fields to saturate the sensor, reducing interference and allowing for reliable detection with fewer or weaker magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple or strong magnets are used to improve detection reliability, then the sensor can reliably detect open or closed position, but the device complexity, cost, and energy consumption increase
Solution Approach 1:
A ferromagnetic material is introduced as an intermediary between the magnet and the magnetic sensor. This ferromagnetic material concentrates and directs the magnetic field lines, creating a stronger and more focused magnetic field at the sensor location without requiring additional magnets or increasing the strength of existing magnets. The ferromagnetic material acts as a flux concentrator, effectively amplifying the magnetic field in the region of interest.
Solution Approach 2:
The magnetic permeability parameter of the ferromagnetic material is utilized to change the distribution and concentration of magnetic field lines. By selecting materials with high magnetic permeability, the system achieves enhanced magnetic field concentration without increasing magnet strength or quantity, thereby maintaining simplicity while improving detection reliability.
2Reliability
If multiple or strong magnets are used to improve detection reliability, then the sensor can reliably detect open or closed position, but the manufacturing cost increases
Solution Approach 1:
The ferromagnetic material serves as a cost-effective intermediary that replaces the need for multiple expensive strong magnets. By using a single magnet combined with a ferromagnetic flux concentrator, the system achieves the same or better detection reliability at lower material and manufacturing costs.
Solution Approach 2:
Changing the magnetic field distribution through the introduction of ferromagnetic material with specific permeability properties allows for cost reduction. The ferromagnetic material is typically cheaper than using multiple high-strength magnets, and its ability to concentrate flux provides an economical solution for improving sensor detection reliability.
3Reliability
If multiple or strong magnets are used to improve detection reliability, then the sensor can reliably detect open or closed position, but the energy consumption increases
Solution Approach 1:
The ferromagnetic material acts as a passive intermediary that enhances the magnetic field without requiring additional energy input. It concentrates the magnetic field lines from the single magnet, achieving improved detection reliability while maintaining the same energy consumption level as the single-magnet configuration.
4Measurement precision
If interference from other magnetic components is present, then the detection accuracy decreases, but using stronger magnets to overcome interference increases complexity and cost
Solution Approach 1:
The ferromagnetic material serves as a flux guide that directs magnetic field lines preferentially toward the sensor, creating a more focused and stronger signal that can overcome background interference from other magnetic components. This intermediary structure enhances signal-to-noise ratio without adding system complexity.
Solution Approach 2:
The ferromagnetic material creates a localized region of high magnetic field concentration at the sensor location, while other regions of the device experience normal magnetic field levels. This local enhancement of magnetic field quality at the detection point improves measurement precision without requiring strong magnets throughout the entire device.
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 design enhances detection reliability, conserves energy, reduces material usage and costs, and simplifies the device by using fewer magnets and lower strengths, improving the out-of-the-box experience and reducing potential failures.
Implementation Method 1
A lid magnetic field is propagated through a ferromagnetic material by a lid magnet when a lid or similar component of the electronic device is in the closed position, thereby placing the lid magnetic field incident upon the magnetic sensor.
Implementation Method 2
A magnetic sensor of the electronic device detects a magnetic field polarity in a detection region of the magnetic sensor
Data Source
AI summary
This disclosure describes an extended closure sensor design for an electronic device. An electronic device (300) senses, with a magnetic sensor (306), an open or a closed position of the electronic device (300). A lid magnetic field is propagated through a ferromagnetic material (304) by a lid magnet (302) when a lid (310) or similar component of the electronic device (300) is in the closed position, thereby placing the lid magnetic field incident upon the magnetic sensor (306). In the open position, the lid magnetic field is materially absent and a bias magnet (308) causes a bias magnetic field to be incident upon the magnetic sensor (306).