The genuineness the genuineness of the detected material and this detected material which are checked the manner null which is checked

摘要

PURPOSE: To provide an object to be detected which is difficult to be forged or altered. CONSTITUTION: The object 10 to be detected is provided with a scanning area 14 and a code display part 18. Fibrous magnetic elements 12 are mixed in the scanning area 14 at random. The information concerning a peculiar detecting signal to be provided corresponding to the distributing state of magnetic permeability at the time of magnetically scanning the scanning area 14 is coded and recorded in the code display part 18. The scanning area 14 is provided with element omitting parts 19 such as punch holes to a degree to change a code so that the distributing state of magnetic permeability can be changed. When the object 10 to be detected is used, corresponding to the conditions of usage, the element omitting parts 19 are provided in the scanning area 14 and afterwards, the scanning area 14 is magnetically scanned again. The new detecting signal provided like this is coded and recorded in the code display part 18 again so that the recorded contents of the object 10 to be detected can be updated each time the element omitting parts 19 are provided.