Title:
INDICATING DEVICES AND APPARATUS
Document Type and Number:
WIPO Patent Application WO1992012401
Kind Code:
A3
Abstract:
PCT No. PCT/GB92/00014 Sec. 371 Date Jun. 15, 1993 Sec. 102(e) Date Jun. 15, 1993 PCT Filed Jan. 3, 1992 PCT Pub. No. WO92/12402 PCT Pub. Date Jul. 23, 1992.A magnetostrictive element, which may be of rectangular shape, is positioned next to a hard magnetic biasing element field with patterns recorded therein which bias the magnetostrictive element to resonate at selected frequencies, particularly harmonics of the fundamental frequency, in response to an alternating interrogating magnetic field at the same frequencies. Data may thus be encoded by selecting the frequencies at which the element will resonate. In addition to resonance at different harmonics, resonance in different modes, particularly longitudinal, transverse or flexural modes may be produced. The device may be applied to article identity systems, such as security systems but also has many other applications.
Inventors:
DAMES ANDREW NICHOLAS (GB)
HYDE PETER JOHN (GB)
HYDE PETER JOHN (GB)
Application Number:
PCT/GB1992/000012
Publication Date:
September 03, 1992
Filing Date:
January 03, 1992
Export Citation:
Assignee:
SCIENT GENERICS LTD (GB)
International Classes:
G01D5/14; G01B17/00; G01D5/48; G01F15/06; G01V15/00; G06F17/40; G06K7/08; G06M1/274; G07C9/00; G08C19/00; G01D; (IPC1-7): G01D5/48; G01F15/06
Foreign References:
| US4510490A | 1985-04-09 | |||
| US4647917A | 1987-03-03 | |||
| US4071818A | 1978-01-31 | |||
| USRE26774E | 1970-01-20 |
Other References:
Patent Abstracts of Japan, vol. 015, no. 12 (C-0795) 10 January 1991, & JP, A, 02261575 (TDK CORP.) 24 October 1990, see abstract
Download PDF: