Mitsubishi Materials Corporation

Tohoku Ricoh Co., Ltd.

Seiro Yahata

Takanori Endo

Masami Miyake

Tadashi Yonezawa

Takashi Tsuchida

Tomohiro Mori

Hideaki Matsuda

Kouichi Ishiyama

Shigenobu Irokawa

Shigeyuki Osawa

Sumio Suzuki

Shigeru Yashima

Masami Miyaki

An antenna for a transponder comprises a magnetic core composed of layered amorphous metallic thin plates or composite plates of soft magnetic flakes and a synthetic resin, and a coil wound on the magnetic core. A transponder comprises two antennas set forth above, and a spiral antenna.

Transponder and antenna

A body detecting element is buried in the ground together with a body such as a metal body and includes a magnetic member acting as a magnetic core, an antenna coil wound around the magnetic member and a capacitor connected to both the ends of the antenna coil for forming a resonance circuit together with the antenna coil. The antenna coil is mounted on the body integrally therewith through an electromagnetic shield member with the outer peripheral surface thereof confronting the outer surface of the body. A body detecting element includes an RFID circuit connected to the antenna coil and mounted on a body integrally therewith such that the outer peripheral surface of the antenna coil confronts the outer surface of the body through an electromagnetic shield member. Even if the body detecting element is mounted on the body such as the metal pipe integrally therewith, it can accurately detect the body because a resonant frequency and the Q value of the coil are not changed. There is almost no possibility that detecting element is broken or moved even if a body other than the above body is dug.

Detection element for objects and detection device using the same

A method and a device for determining the amount of ink or similar liquid existing in a container are disclosed. A resonance circuit is arranged on the container storing the liquid. A voltage having a preselected frequency is applied to a drive coil located outside of the container to thereby induce a voltage having a preselected frequency in the resonance circuit. The voltage induced in the resonance circuit, in turn, induces a voltage having a preselected frequency in a sense coil also located outside of the container. The amount of liquid in the container is determined in terms of the voltage induced in the sense coil.

Method and device for determining the amount of a liquid existing in a container

A burglar detection apparatus has a tag,that includes a resonance circuit. The tag is preferably contained with an object,whose theft is desired to be detected. The tagged object may be placed in a drawer,which is contained in a box,. A tag detection sensor,is installed in the box and detects whether the tag,is present in the drawer,. Also, a drawer sensor,detects whether the drawer is opened. Based on respective detection outputs of the tag detection sensor,and the drawer sensor,, a control circuit,controls an alarm,. Advantageously, the apparatus can be installed in a comparatively small space, does not malfunction even if subjected to large amounts of electrical noise, and reliably detects the presence or absence of a tag even if the tag is located near a metal object.

Apparatus for detecting theft by a radio wave

A theftproof tag which is effective regardless of the material of the article to which it is attached. There is neither a change in resonance of a resonance circuit nor a decrease in the Q value due to the material of the surface of a theft monitored article, thereby decreasing errors in the operation of a theft monitor. The theftproof tag has a resonance circuit resonating to an electric wave at a specified frequency transmitted from a transmitting antenna, and having a coil unit and a capacitor electrically connected to both ends of the coil unit. The coil unit has a magnetic core member made of a composite material composed of a powder or flakes of a soft magnetic metal, and a plastic, and a winding wound around the periphery of the magnetic core member and connected to the capacitor, a portion of the magnetic core member facing the attaching surface of the article.

Theftproof tag

An anti-theft tag for attachment to a theft-monitored article including a resonance circuit which resonates radio waves of a predetermined frequency transmitted from an antenna, and a shielding coil having at least two terminals. The shielding coil is disposed between the resonance circuit and the article when the anti-theft tag is attached to the article, and the at least two terminals are short-circuited.

Anti-theft tag

An anti-theft tag which when attached to an article containing a conductive surface properly transmits a signal to a control device to generate an alarm if the article has been taken without permission. The anti-theft tag includes a resonance circuit and a soft magnetic material disposed between an attaching face of the article and the resonance circuit. The soft magnetic material allows the anti-theft tag to provide a resonance frequency which is independent of the material the anti-theft tag is attached to. The soft magnetic material may be composed of, for example, any one of an amorphous alloy, PERMALLOY, electromagnetic soft iron, silicon steel sheet, sendust alloy, Fe--Al alloy, and soft magnetic ferrite. The soft magnetic material may also be a composite material of soft magnetic material flakes and a plastic.

Growing community of inventors

Tokyo, Japan

Seiro Yahata