Patent Number: 6,528,991

Title: Magnetic position measurement system with field containment means

Abstract: A magnetic field position and orientation measurement system contains, confines and re-directs the magnetic field from one or more transmitters such that the fields are attenuated in areas outside of the operating volume in areas where metallic objects are commonly found. An attenuator made of a highly permeable material such as ferrite or mumetal may be placed on top of a conductive plate. The permeable attenuator may be as thin as 0.001 inches. on top of the permeable attenuator, a transmitter system is placed including at least three transmitters. In one embodiment, the transmitter consists of a PC board carrying the transmitter. The transmitter system, the permeable attenuator and the conductive plate, where used, may only be from 1/2 inch to 5/8 of an inch in thickness combined. The permeable attenuator may have a flat, planar configuration. Alternatively, it may be made to resemble, in cross-section, a cake pan having a flat central region with uplifted peripheral edges. Alternatively, the permeable attenuator may have a generally flat configuration with peripheral edges that taper outwardly from the top surface thereof to the bottom surface thereof with the taper making an angle with the bottom surface in the range of, preferably, 30.degree. to 85.degree.. The conductive plate is optional.

Inventors: Ashe; Westley (Milton, VT)

Assignee: Ascension Technology Corporation

International Classification: A61B 5/06 (20060101); G01B 007/30 ()

Expiration Date: 03/04/2020