Browse Prior Art Database

Ferrofluid Display Switch Selector

IP.com Disclosure Number: IPCOM000083296D
Original Publication Date: 1975-Apr-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Romankiw, LT: AUTHOR [+3]

Abstract

This is a ferrofluid display system, in which a ferrofluid (colloidal suspension of magnetite separated by surfactants in a first fluid) is suspended in a liquid with which it is immiscible. Droplets of ferrofluid are generated and then manipulated by rotating magnetic fields along prescribed paths, under control of permeable members.

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Ferrofluid Display Switch Selector

This is a ferrofluid display system, in which a ferrofluid (colloidal suspension of magnetite separated by surfactants in a first fluid) is suspended in a liquid with which it is immiscible. Droplets of ferrofluid are generated and then manipulated by rotating magnetic fields along prescribed paths, under control of permeable members.

An externally activated magnetic ferrofluid droplet switch selector 9 sandwiched between two plates, not shown, is shown in Fig. 1. Fig. 2 is an enlarged cross section of the switch taken along lines 2-2 near X in Fig. 1. Generator 10 constantly forms ferrofluid droplets 7 which pass onto an externally magnetized shift register A in area 5.

Selector 9 permits desired droplets 7 to enter the display area 6 by external signals applied to current lines 16, to generate a magnetic field to control transfer of the droplets 7 from area 5 to area 6. Current in line 16 locally increases the magnetic field gradient for a short duration, and coincidentally diverts a ferrofluid bubble 7 from preliminary register A to display shift register B.

Selector 9 operates on the following principle: Shift register A constantly picks up fresh bubbles 7 from generator 10. The size of a bubble 7 is controlled by the applied in-plane magnetic field and the distance of generator 10 from the pickup tooth 8 of register A. The inplane horizontal magnetic field rotates clockwise changing the orientation of the magnetic field in register A. As a result, a bubble 7 propagates along path 17 toward a magnetic switch 14 where the distance X between pickup tooth 11 of display shift register B (which is also externally magnetized by the rotating...