Magnetic Sensor with Shared Terminals for Miniaturization
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Solution Overview
Problem
Existing magnetic sensors face challenges in miniaturization and maintaining high-performance sensor characteristics as the number of MR elements increases, leading to complex manufacturing processes and increased sensor dimensions.
Innovation Solution
The magnetic sensor design features a shared power supply and ground terminal among multiple electric current path units, with each unit comprising series-connected magnetoresistance effect elements, and a conductive film for wiring, allowing for compact configuration and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple MR elements are laminated with insulating films interposed therebetween to enhance detection accuracy, then measurement precision is improved, but device complexity increases due to the need for through-hole connections in each insulating film
Solution Approach 1:
Multiple MR elements are formed in the same magnetoresistance effect film layer rather than laminating separate films, allowing parallel formation and connection without requiring through-holes in multiple insulating films. This merging approach maintains detection accuracy while significantly simplifying the manufacturing process.
Solution Approach 2:
The patent transitions from a vertical lamination structure (multiple films stacked) to a planar structure (multiple elements in the same layer), changing the dimensional arrangement to eliminate the need for through-hole connections while maintaining the ability to form multiple MR elements.
2Measurement precision
If multiple MR elements are formed using magnetoresistance effect films of different layers to enhance detection accuracy, then measurement precision is improved, but reliability decreases due to difficulty in obtaining stable high-performance characteristics
Solution Approach 1:
Multiple MR elements are formed using the same magnetoresistance effect film layer with uniform material properties and formation conditions, ensuring homogeneous characteristics across all elements. This homogeneity guarantees stable and reproducible high-performance characteristics, eliminating the reliability issues associated with multi-layer different-film approaches.
3Measurement precision
If the number of resistor elements is increased to enhance position detection accuracy, then measurement precision is improved, but length of stationary object increases due to lack of countermeasures against dimension increase
Solution Approach 1:
Multiple MR elements are arranged in the same film layer with optimized spatial positioning, allowing closer packing and more efficient use of space. This merging approach enables increasing the number of elements for higher detection accuracy without proportionally increasing the overall sensor dimension.
Solution Approach 2:
The patent arranges multiple MR elements in a planar configuration within the same layer rather than stacking them vertically, enabling more elements to be accommodated in a compact footprint and preventing excessive dimension increase while enhancing position detection accuracy.
4Measurement precision
If the number of MR elements is increased to enhance position detection accuracy, then measurement precision is improved, but device complexity increases due to lack of countermeasures against manufacturing process complication
Solution Approach 1:
Multiple MR elements are formed simultaneously in the same magnetoresistance effect film layer using a unified formation process, eliminating the need for separate film deposition and alignment steps for each element. This merging approach allows increasing the number of elements without proportionally increasing manufacturing process complexity.
Solution Approach 2:
The patent employs a planar arrangement of multiple MR elements in the same layer, which can be formed using standard photolithography and etching processes without requiring complex multi-layer alignment, thereby enabling high-precision position detection with manageable manufacturing complexity.
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 effectively suppresses the increase in sensor dimension, enables miniaturization, and stabilizes high-performance sensor characteristics, even with a higher number of MR elements, while simplifying the manufacturing process.
Implementation Method 1
an Ni—Fe alloy film and an Ni—Fe—Co alloy film capable of bringing out an anisotropic magnetoresistance effect (AMR effect)
Data Source
AI summary
For each of electric current path units each including series-connected resistor elements, one end is electrically connected with power supply terminal Vcc, the other end is electrically connected with ground terminal GND, and connection portion between the resistor elements is electrically connected with output terminals Vo1-Vo4. Resistor element constituting each of the electric current path units is a magnetoresistance effect element formed of magnetoresistance effect film, the power supply terminal and ground terminal are each shared among all the electric current path units. All the electric current path units are formed to contact one surface of insulating film; and with use of conductive film disposed to contact the other surface of the insulating film, power supply connection wiring for sharing the power supply terminal and ground connection wiring for sharing the ground terminal are formed.