Using high-permeability magnetic elements randomly scattered in the objects
US5451759A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1994 |
| Grant date | Sep 19, 1995 |
| Priority date | — |
| Expiry date | Jun 21, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07F7/125
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An object to be checked has a scanning region which contains a large number of magnetic elements scattered at random. Each of the magnetic elements is made up of an element main body formed of a high molecular material, and magnetic metal powder contained in the element main body. A processing apparatus employed for checking whether or not the object is authentic has a magnetic sensor which is made up of a pair of MR elements and a magnet. The MR elements are arranged side by side in the direction in which the scanning region is scanned. In the manufacturing process of the object, a detection signal which is based on variations in the output ratio between the MR elements is produced, with the scanning region of the object being moved. The detection signal is converted into a cipher code, and this cipher code is recorded in a code indicator section. When the object is checked for authenticity, a detection signal obtained by scanning the scanning region is collated with the cipher code recorded in the code indicator section. When the detection signal and the cipher code agree with each other, the object is determined as being authentic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.