TMR Position Sensing Mechanism with Perpendicular Magnetic Moments
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Solution Overview
Problem
Existing position sensing technologies using Hall sensors face limitations in low power consumption and high sensitivity, particularly in applications requiring low power and high sensitivity, and the assembly of discrete sensing elements for incremental and absolute column magnetic tracks increases costs and affects accuracy.
Innovation Solution
A position sensing mechanism utilizing tunneling magneto-resistors with perpendicular magnetic moments in a single structure for both absolute and incremental column sensing, integrated on a base plate, eliminating the need for separate assembly of sensing elements and ensuring accurate position sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall sensors are used for position sensing, then position detection capability is provided, but power consumption is high and sensitivity is low
Solution Approach 1:
The patent changes the sensing mechanism from Hall effect to tunneling magnetoresistive effect, utilizing perpendicular magnetic moments in reference and free layers to achieve high sensitivity with low power consumption. The TMR effect provides a larger resistance change ratio compared to Hall sensors, enabling detection of weaker magnetic field changes while consuming less power.
Solution Approach 2:
The patent employs composite magnetic layer structures including reference layers, free layers, and tunneling barriers in the TMR sensing elements. This composite structure combines materials with different magnetic properties to achieve both high sensitivity and low power consumption characteristics simultaneously.
2Measurement precision
If discrete Hall sensing elements are used for absolute and incremental column sensing, then position information can be obtained, but assembly procedures are complex and alignment accuracy is affected
Solution Approach 1:
The patent merges the absolute column and incremental column sensing functions into a single integrated sensing element. The TMR sensing structure simultaneously provides both absolute position information (from the reference layer) and incremental position changes (from the free layer), eliminating the need for separate discrete sensing elements and their complex assembly procedures.
Solution Approach 2:
The integrated TMR sensing element performs multiple functions: it detects both absolute magnetic field orientation and incremental magnetic field changes. This multi-functional design allows a single sensing element to replace what previously required multiple discrete elements, simplifying the overall device structure and assembly process.
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 enhances sensitivity and reduces power consumption while simplifying the assembly process, improving the accuracy and yield of position sensing mechanisms by using the same structure for both types of sensing elements on the same plane.
Implementation Method 1
uses a tunneling magneto-resistor for sensing of positions
Implementation Method 2
obtain position analysis information by sensing changes of a magnetic field angle caused by the movement of the magnetic track
Data Source
AI summary
A position sensing mechanism provided by the invention comprises an encoding element as a sensing signal source, a reading element for sensing signals of the signal source, and a processing unit for receiving and analyzing sensing signals output by the reading element, the position sensing mechanism has a main technical feature lying in a magneto-resistive unit in the reading element for sensing signals of the signal source being a tunneling magneto-resistor (TMR), and two layers of magnetic moments of a reference layer and a free layer of the tunneling magneto-resistor being perpendicular to each other, and in the reference layer and the free layer with the magnetic moments being perpendicular to each other, the magnetic moment of one of the layers is parallel to a film surface, and the magnetic moment of the other layer is perpendicular to the film surface.