Magnetic Switch With Dual Detectors For Interference Immunity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic field sensors are sensitive to external magnetic fields, which can adversely affect their switching properties and reliability.
Innovation Solution
A switch with a magnet arrangement and two magnetic field detectors, where the detectors' sensitive surfaces are aligned parallel and movable relative to each other, allowing for differential signal processing to achieve interference immunity, with an evaluation unit determining switching signals based on differences in detected magnetic field components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a magnetic field sensor is used as a contactless magnetic switch, then contactless switching is achieved, but the sensor reacts sensitively to external magnetic fields which adversely affects switching properties
Solution Approach 1:
The patent divides the sensing function into two separate magnetic field detectors instead of using a single sensor. Each detector measures the magnetic field at a different location, and their signals are evaluated differentially. This segmentation allows the system to distinguish between the controlled magnetic field (from the movable magnet) and external magnetic field interference, thereby maintaining contactless switching while improving reliability.
Solution Approach 2:
The patent introduces an evaluation unit as an intermediary between the magnetic field detectors and the switching output. This evaluation unit processes the signals from both detectors, compares them, and determines the switching state based on the difference between the signals. The intermediary filters out external magnetic field interference while preserving the intended switching signal.
2Reliability
If two magnetic field detectors are used with parallel sensitive surfaces for differential measurement, then resistance to external field interference is improved, but device complexity increases
Solution Approach 1:
The patent combines the two magnetic field detectors and the evaluation unit into an integrated switch device. The detectors are positioned with their sensitive surfaces parallel to each other, and the evaluation unit is integrated within the same device housing. This merging approach achieves interference immunity through differential measurement while keeping the overall device structure compact and manageable.
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
The solution provides reliable switching even in the presence of external magnetic fields by ensuring that the detected magnetic field components differ in sign between the detectors, enhancing resistance to external interference and maintaining consistent switching behavior.
Implementation Method 1
The first magnetic field detector and the second magnetic field detector can be configured as a magnetoresistance effect sensor, a Hall effect sensor and/or a giant magnetoresistance effect sensor
Implementation Method 2
The first magnetic field detector and the second magnetic field detector can be configured as a magnetoresistance effect sensor, a Hall effect sensor and/or a giant magnetoresistance effect sensor
Data Source
Figure 1~3
Figure 4~6
Figure 7~11
AI summary
The present invention relates to a switch having a magnet arrangement with at least one first magnet (3) and one first magnetic field detector (1) which outputs a first electrical signal, and a second magnetic field detector (2) which outputs a second electrical signal. Sensitive surfaces of the first magnetic field detector (1) and of the second magnetic field detector (2) are oriented parallel to one another, and the magnet arrangement is arranged movably between the first magnetic field detector (1) and the second magnetic field detector (2) in a relative movement parallel to the sensitive surfaces. A vector of the magnetic field detected by the first magnetic field detector (1) and a vector of the magnetic field detected by the second magnetic field detector (2) in a first end position of the relative movement and in a second end position of the relative movement have a different sign in just one detected component of the vector of the magnetic field. An electrical or electronic evaluation unit (4) is arranged downstream of the first magnetic field detector (1) and the second magnetic field detector (2) and is designed to determine a difference between the first electrical signal and the second electrical signal.