Tag for theft prevention

Abstract

A tag for theft prevention is provided for decreasing the porion covering the inside of a container case as much as possible while being capable of carrying out detection without being affected adversely by a recording medium. The tag for theft prevention includes a detecting circuit which is positioned at the circumference edge of at least one of the sides of a container case in the thickness direction of the recording medium and is capable of detecting electric waves. Further, it includes a resonating circuit which is positioned in one specific side perpendicular to one side of the container case and is closely positioned with the detecting circuit or is connected to the detecting circuit in a theft preventing system which can detect whether or not electric wave absorption occurs by the passage of the resonating circuit provided on the container case containing a recording medium such as a CD or a protective case covering the container case, between a gate with a built-in transmission antennae and another gate with a built-in receiving antennae.

Dependencies are inferred from the claim text.