Magnetic Field Sensor with Embedded Magnet Encapsulation
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Solution Overview
Problem
Modern magnetic field sensors exposed to high thermal and mechanical stresses in applications like camshaft sensors require a method for producing robust and long-lasting sensors with a premagnetization field, which conventional sensors with permanent magnets fail to adequately address.
Innovation Solution
A method involving a chip carrier with semiconductor chips and a magnetic layer carrier, where the magnetic layer is subdivided into permanent magnets and covered with a magnet encapsulation, ensuring robustness and longevity by embedding the permanent magnet within a magnet encapsulation that extends to the free surface of the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet is used to produce a premagnetization field in magnetic field sensors, then the sensor performance is improved, but the sensor becomes vulnerable to mechanical and thermal stresses that reduce its lifetime
Solution Approach 1:
The patent applies beforehand cushioning by embedding the permanent magnet in a magnet encapsulation made of stress-absorbing material before the sensor is exposed to mechanical and thermal stresses. This encapsulation acts as a protective buffer that absorbs stresses during operation, preventing direct transmission of harmful forces to the permanent magnet and semiconductor chip, thereby extending sensor lifetime in harsh environments
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure consisting of the permanent magnet embedded in a magnet encapsulation material, which is itself embedded in a semiconductor chip encapsulation. This composite structure combines materials with different mechanical and thermal properties to simultaneously protect the permanent magnet from stresses while maintaining the sensor's functional performance
2Strength
If the permanent magnet is exposed to mechanical stresses during operation, then the sensor can maintain direct contact with the magnetic layer, but the magnet's integrity and the sensor's longevity are compromised
Solution Approach 1:
The patent applies the nested doll principle by creating a nested encapsulation structure where the permanent magnet is embedded within an inner magnet encapsulation, which is itself embedded within an outer semiconductor chip encapsulation. This nested arrangement provides multiple layers of mechanical protection, allowing the sensor to maintain robustness while protecting the permanent magnet from damage over extended operational periods
3Ease of manufacture
If conventional production methods are used without magnet encapsulation, then the manufacturing process is simpler, but the sensor lacks protection against thermal and mechanical stresses
Solution Approach 1:
The patent applies preliminary action by forming the magnet encapsulation around the permanent magnet during the production process, before the sensor is assembled and deployed. This preliminary encapsulation step integrates the protection function into the manufacturing process itself, allowing the sensor to gain stress resistance without requiring complex post-production modifications or additional assembly steps
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 enhances the robustness and longevity of magnetic field sensors by creating a strong and evenly distributed premagnetization field, protecting the sensors from mechanical and thermal stresses, thereby extending their lifespan.
Implementation Method 1
a permanent magnet for producing this premagnetization field
Data Source
AI summary
A magnetic field sensor having a semiconductor chip is proposed, the semiconductor chip having at least one magnetic field sensor element, the semiconductor chip being embedded in a semiconductor chip encapsulation, having a permanent magnet, the permanent magnet being embedded in a magnet encapsulation, wherein an interface between the semiconductor chip encapsulation and the magnet encapsulation extends as far as a free surface of the magnetic field sensor. Methods for producing a magnetic field sensor are furthermore disclosed.