Anti-theft protection device

摘要

An anti-theft protection device which avoids spurious alarms (false alarms) has a label (10), an alarm buzzer (16) and a controller (15) which is connected to the label in order to detect a label state which is different from the initial state of the label, in order to operate, if appropriate, the alarm buzzer. The label (10) has an adhesive layer (17), a conductive layer (11) formed on one side of the adhesive layer (17) and a support (18) formed on the conductive layer. The other side of the adhesive layer is fastened to the article to be protected. A resistance of the conductive layer is detected by the controller. When the other state of the label (10), corresponding to the change in resistance of the conductive layer, is detected by the controller, the latter operates the alarm buzzer (16). When the label is pulled off the article by force, the adhesive layer remains on the article, likewise part of the conductive layer. This means that the conductive layer is partially removed, which is accompanied with an increase in the resistance of the conductive layer. This change in resistance is detected by the controller and interpreted as an indication that the label has been pulled off the article. <IMAGE>