Systems for Visualizing and Mapping Magnetic Fields in Space and Time

Magneto-Optic Sensors and Sensor Systems from Matesy utilize the rotation of polarized light in the Sensor to enable the magnetic field distribution external to a flat surface to be captured. Complex static magnetic field patterns from permanent magnets in linear or disc encoders, magnetic codes, or magnetic actuators can be rapidly imaged for product design, magnetizer tool development or quality control of magnet production by placing the object on the Sensor surface. Areas of up to 75 mm diameter are available with a single Sensor. Magneto-Optic Sensors are presently available in four magnetic field ranges of ±2.5mT to ±160mT full-scale with a ±300mT Sensor presently in development. Field amplitude resolution is approximately ±1% of full-scale with an accuracy of about ±5% of full-scale.

The spatial and time resolution Matesy Magneto-Optic Systems are dependent on the optical system, camera and image processing. In the standard CMOS-MagView system, resolution can be down to 25 µm and 1 sec respectively. In video mode it is feasible to continuously image time varying magnetic patterns such as created by grain boundary movement in magnetic steels as a function of imposed external field or the movement of magnetic fluids in micro-machined channels. Field amplitude versus position can be displayed as a 3-D image of B versus x and y position, or as B along a selected line in the x-y plane. An overview of applications to date is available here.

Senis offer their high accuracy Three-Axis Magnetic Field Transducers in Magnetic Field Mapping Systems. These Transducers are based on a Senis Field Sensor Integrated Circuit that simultaneously measures Bx, By and Bz within a measuring volume of 150 x 10 x 150 µm  to provide high spatial and angular resolution. The Mappers provide x-, y-, z- motion control of the Field Sensor over a 135mm or 500mm cubical volume. Position location resolution can be 10 µm  or 1 µm with scanning speeds of 50mm/sec or 100mm/sec. A Rotating Stage is available as an option. Standard field ranges are available from ±20 mT to ±T full scale and multiple ranges are available as options. Measurement accuracy for each component of Bx, By, and Bz is ±0.5% or ±0.1% of full-scale with a frequency response from dc to 2.5 kHz (-3dB) as standard and 25 kHz optional. A Touch Sensor Probe Mounting option immediately stops the mapping in the event the Probe touches an obstacle. A Position Calibration Tool enables accurate calibration of the Probe magnetic center with respect to mechanical axes. Unique options include a Sliding Probe that touches the surface to be mapped and enables accurate field mapping to within 100 µm of the surface.