| 摘要 |
<p>PURPOSE: To detect removal of a tag from an object by generating a different tamper detection signal when the tag is removed and fitted to a substitute object. CONSTITUTION: After a reference plate 19 forming a variable capacitance capacitor with an element is fixed to an object 12, a tag main body is fitted to cover the plate 19, the plate 19 is capacitance-coupled with an electrode array 16 and a pickup plate 17 an when the device is challenged, a tamper detection signal is generated. Then the tag main body is adhered to the object 12 and the tag is challenged and an interrogator records the taper detection signal in 12-bit. For example, when the electrode array 16 and the reference plate 19 are placed on the object with the tag at first and specific relative positions, a specific tamper detection signal is generated. However, when the electrode array 16 and the reference plate 19 are placed at 2nd relative positions, a different tamper detection signal is generated to detect a relative position shift.</p> |
