Patent ID: 9721705
Date: 2017-08-01
CPC Classifications: B22F,B41M,C09D,H01F

Claim:
1. Magnetic particle having a high-reflective protective membrane, comprising: a magnetic core; a first shell formed on an outer surface of the magnetic core and made out of a dielectric material; a second shell formed on an outer surface of the first shell and made out of a metallic material; and a high-reflective protective membrane formed on an outer surface of the second shell; wherein the high-reflective protective membrane has a single layer and an optical thickness of (0.42*N)−0.17 to (0.42*N)+0.17 wavelength, where N is an integer, or wherein the high-reflective protective membrane has multiple layers having a low-refractive-index membrane having an optical thickness in the range of 0.15 to 0.35 wavelength formed on an outer surface of the second shell and a high-refractive-index membrane having an optical thickness in the range of 0.15 to 0.35 wavelength formed on an outer surface of the low-refractive-index membrane, wherein the first shell has a single-layer structure, and the dielectric material of the first shell comprises titanium dioxide, wherein the second shell has a single-layer structure, and the metallic material of the second shell comprises silver, wherein the low-refractive-index membrane is made out of silicon dioxide and optionally one or more of a group consisting of magnesium fluoride, polystyrene, polymethyl methacrylate, polystyrene-co-butadiene, vanadium pentoxide, cadmium oxide, polyisobutylene, and polyethylene, and wherein the high-refractive-index membrane is made out of titanium dioxide and optionally one or more of a group consisting of aluminum oxide, zinc oxide, zirconium oxide, and chromium oxide.