NON-CHARGED MAGNETIC FINE PARTICLE BY IRRADIATION WITH RADIATION

摘要

PROBLEM TO BE SOLVED: To realize manufacture of non-charged magnetic fine particles required for constructing a system wherein secondary aggregation and precipitation are prevented and a historical display image can be erased in a magnetophoretic display device and a reflection type electromagnetophoretic display device utilizing magnetic phoresis of the non charged magnetic fine particles. SOLUTION: Ferromagnetic fine particles are added to a polymer fine particle material, the mixture thereof is polymerized in a perfectly spherical fine particle structure and irradiated with aγ-ray for removing static electricity of the polymer fine particle material to obtain pure magnetic fine particles. The magnetic fine particles have≥1×10-6Wb magnetic charge and a function wherein secondary aggregation and precipitation are prevented and the historical display image can be erased and thereby the high speed magnetophoretic display device and a composite display device of the reflection type electromagnetophoretic display device and the like are realized. The non-charged magnetic fine particles are dispersed in a petroleum-based or a silicone oil-based transparent insulating liquid or the like and a magnetic field is applied to the resultant dispersed system to realize the monochrome and color transmission type mgnetophoretic display device and the reflection type electromagnetophoretic display device. COPYRIGHT: (C)2005,JPO&NCIPI