Title :
Integration of polymer bonded magnets into magnetic sensors
Author :
Elian, Klaus ; Theuss, Horst
Author_Institution :
Infineon Technol., Regensburg, Germany
Abstract :
This paper introduces a novel assembly and manufacturing technology for integrating permanent magnets into magnet sensor modules by use of plastic bonded magnets. High precision speed sensors in automotive applications, e.g. in anti-blocking-system or engine management, are based on a magnetic measurement principle [1]. Typical sensor modules contain a semiconductor based sensor chip and a permanent magnet providing the necessary bias field (see Fig. 1). This field is modulated by a passing external gear wheel out of material with high magnetic permeability, which is part of the magnetic circuit. The wheel speed can directly be determined by measuring the frequency of the magnetic field modulation. Permanent magnets are often assembled in a sequential pick and place process. We report a novel assembly technology by direct molding of thermoplast bonded magnets onto a chip carrier containing pre-assembled sensors. We will show, that this offers the following advantages: - Highest accuracy - Optimum working point, in particular for GMR sensors - High throughput by efficient parallel process - Simplification of the module assembly.
Keywords :
magnetic circuits; magnetic fields; magnetic permeability; magnetic sensors; permanent magnets; polymers; GMR sensors; antiblocking-system; assembly technology; automotive applications; bias field; bonded magnets; chip carrier; direct molding; engine management; high precision speed sensors; magnet sensor modules; magnetic circuit; magnetic field modulation; magnetic measurement principle; magnetic permeability; manufacturing technology; module assembly; parallel process; passing external gear wheel; permanent magnet integration; plastic bonded magnets; polymer bonded magnets; semiconductor based sensor chip; sequential pick and place process; Assembly; Magnetic fields; Magnetic semiconductors; Magnetomechanical effects; Permanent magnets; Sensors; Wheels;
Conference_Titel :
Electronics System-Integration Technology Conference (ESTC), 2014
Conference_Location :
Helsinki
DOI :
10.1109/ESTC.2014.6962754