Method for individually encapsulating magnetic particles
AssigneeMagnavox Government and Industrial Electronics Company
InventorLawrence L. Lee
Life of this patent
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Abstract
A method for encapsulating magnetic particles by enclosure within oil drops, mixing in an aqueous solution and dispersing the oil drops with the enclosed particles by application of an alternating magnetic field. The dispersed and oil-covered particles are microencapsulated with at least one type of polymer.
Claims18
A method for encapsulating a preselected average number of magnetized particles which may be rotated within individual capsules for use in a magnetic particle display comprising the steps of:
- immersing the particles in a liquid internal phase;
- forming drops of the internal phase containing said particles;
- suspending said drops in a liquid continuous phase;
- applying a varying magnetic field to said suspension for dispersing said particles and forming smaller drops with a reduced number of particles in each drop, the frequency of said field variations being selected according to the desired number of particles in individual drops;
- microencapsulating individual ones of said drops to form capsules containing drops in which said particles are rotatable.
A method according to claim 17 wherein the step of applying the alternating magnetic field further comprises varying the intensity and frequency of said field to control dispersal of the particles.
A method for dispersing a preselected average number of magnetized particles, the particles being enclosed in a discrete amount of internal phase to permit rotation of the particle therein, comprising the following sequential steps:
- 1. immersing the particles in a liquid internal phase;
- 2. suspending internal phase drops containing the immersed particles in a liquid continuous phase;
- and
- 3. applying a varying magnetic field to said suspension for dispersing said particles within their associated drops of said internal phase to control the size of the drops and the number of particles in the drops.
Dependencies are inferred from the claim text.