Magnetic fluid thin film displays, monochromatic light switch and tunable wavelength filter
US5948321A · kind A · utility
Inventors
Key dates
| Filing date | Apr 4, 1997 |
| Grant date | Sep 7, 1999 |
| Priority date | — |
| Expiry date | Apr 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2201/305
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods for preparing homogeneous magnetic fluid compositions capable of forming ordered one dimensional structures or two dimensional lattices in response to externally applied magnetic fields are disclosed. The compositions are prepared using improved co-precipitation methods in which the steps of the procedure have been tuned to reduce sample heterogeneity. Fe.sub.3 O.sub.4 particles are coated with a surfactant and dispersed in a continuous carrier phase to form a homogeneous magnetic fluid composition. The ability of the composition to generate ordered structures can be tested by holding a magnet near a thin film of the compositions and observing the formation of colors in the region near the magnet. Methods for controlling the characteristic spacing of the ordered structures formed by the composition are also disclosed. Relevant parameters include the thickness of the film, the strength and orientation of the externally applied magnetic field, the rate of change of field strength, the volume fraction of the magnetic particles dispersed in the continuous phase, and the temperature of the film. The homogeneous magnetic fluid composition is useful for the manufacture of liquid c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.